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Chapter 6

Fractions

Class - 6 ML Aggarwal Understanding ICSE Mathematics



Exercise 6.1

Question 1

Write the following division as fractions:

(i) 3 ÷ 7

(ii) 11 ÷ 78

(iii) 113 ÷ 128

Answer

(i) 3 ÷ 7

A division a ÷ b can be written as the fraction ab\dfrac{a}{b}.

So, 3 ÷ 7 = 37\dfrac{3}{7}.

Hence, 3 ÷ 7 = 37\dfrac{3}{7}.

(ii) 11 ÷ 78

A division a ÷ b can be written as the fraction ab\dfrac{a}{b}.

So, 11 ÷ 78 = 1178\dfrac{11}{78}.

Hence, 11 ÷ 78 = 1178\dfrac{11}{78}.

(iii) 113 ÷ 128

A division a ÷ b can be written as the fraction ab\dfrac{a}{b}.

So, 113 ÷ 128 = 113128\dfrac{113}{128}.

Hence, 113 ÷ 128 = 113128\dfrac{113}{128}.

Question 2

Write the following fractions in words:

(i) 27\dfrac{2}{7}

(ii) 310\dfrac{3}{10}

(iii) 1528\dfrac{15}{28}

Answer

(i) 27\dfrac{2}{7}

Hence, 27\dfrac{2}{7} in words is two-seventh.

(ii) 310\dfrac{3}{10}

Hence, 310\dfrac{3}{10} in words is three-tenth.

(iii) 1528\dfrac{15}{28}

Hence, 1528\dfrac{15}{28} in words is fifteen-twenty eighth.

Question 3

Write the following fractions in number form:

(i) one-sixth

(ii) three-eleventh

(iii) seven-fortieth

(iv) thirteen-one hundred twenty fifth

Answer

(i) one-sixth

Hence, one-sixth in number form is 16\dfrac{1}{6}.

(ii) three-eleventh

Hence, three-eleventh in number form is 311\dfrac{3}{11}.

(iii) seven-fortieth

Hence, seven-fortieth in number form is 740\dfrac{7}{40}.

(iv) thirteen-one hundred twenty fifth

Hence, thirteen-one hundred twenty fifth in number form is 13125\dfrac{13}{125}.

Question 4

What fraction of each of the following figures is shaded part?

What fraction of each of the following figures is shaded part. Fractions, ML Aggarwal Understanding Mathematics Solutions ICSE Class 6.
What fraction of each of the following figures is shaded part. Fractions, ML Aggarwal Understanding Mathematics Solutions ICSE Class 6.
What fraction of each of the following figures is shaded part. Fractions, ML Aggarwal Understanding Mathematics Solutions ICSE Class 6.

Answer

(i) Total parts = 7

Shaded parts = 4

Fraction = Shaded partsTotal parts=47\dfrac{\text{Shaded parts}}{\text{Total parts}} = \dfrac{4}{7}.

Hence, fraction = 47\dfrac{4}{7}.

(ii) Total parts = 8

Shaded parts = 3

Fraction = Shaded partsTotal parts=38\dfrac{\text{Shaded parts}}{\text{Total parts}} = \dfrac{3}{8}.

Hence, fraction = 38\dfrac{3}{8}.

(iii) Total parts = 4

Shaded parts = 12\dfrac{1}{2}

Fraction = Shaded partsTotal parts=124=12×4=18\dfrac{\text{Shaded parts}}{\text{Total parts}} = \dfrac{\dfrac{1}{2}}{4} = \dfrac{1}{2 \times 4} = \dfrac{1}{8}.

Hence, fraction = 18\dfrac{1}{8}.

(iv) Total parts = 4

Shaded parts = 1

Fraction = Shaded partsTotal parts=14\dfrac{\text{Shaded parts}}{\text{Total parts}} = \dfrac{1}{4}.

Hence, fraction = 14\dfrac{1}{4}.

(v) Total parts = 6

Shaded parts = 1

Fraction = Shaded partsTotal parts=16\dfrac{\text{Shaded parts}}{\text{Total parts}} = \dfrac{1}{6}.

Hence, fraction = 16\dfrac{1}{6}.

(vi) Total parts = 10

Shaded parts = 3

Fraction = Shaded partsTotal parts=310\dfrac{\text{Shaded parts}}{\text{Total parts}} = \dfrac{3}{10}.

Hence, fraction = 310\dfrac{3}{10}.

(vii) Total parts = 7

Shaded parts = 3

Fraction = Shaded partsTotal parts=37\dfrac{\text{Shaded parts}}{\text{Total parts}} = \dfrac{3}{7}.

Hence, fraction = 37\dfrac{3}{7}.

(viii) Total parts = 4

Shaded parts = 2

Fraction = Shaded partsTotal parts=24\dfrac{\text{Shaded parts}}{\text{Total parts}} = \dfrac{2}{4}.

Hence, fraction = 24\dfrac{2}{4}.

(ix) Total parts = 9

Shaded parts = 4

Fraction = Shaded partsTotal parts=49\dfrac{\text{Shaded parts}}{\text{Total parts}} = \dfrac{4}{9}.

Hence, fraction = 49\dfrac{4}{9}.

Question 5

Shade the parts of the following figures according to given fractions:

Shade the parts of the following figures according to given fractions: Fractions, ML Aggarwal Understanding Mathematics Solutions ICSE Class 6.
Shade the parts of the following figures according to given fractions: Fractions, ML Aggarwal Understanding Mathematics Solutions ICSE Class 6.

Answer

(i) 34\dfrac{3}{4}

The figure (square) is divided into 4 equal parts. Shade 3 parts out of 4.

Shade the parts of the following figures according to given fractions: Fractions, ML Aggarwal Understanding Mathematics Solutions ICSE Class 6.

(ii) 16\dfrac{1}{6}

The figure (circle) is divided into 6 equal parts. Shade 1 part out of 6.

Shade the parts of the following figures according to given fractions: Fractions, ML Aggarwal Understanding Mathematics Solutions ICSE Class 6.

(iii) 14\dfrac{1}{4}

The figure (triangle) is divided into 4 equal parts. Shade 1 part out of 4.

Shade the parts of the following figures according to given fractions: Fractions, ML Aggarwal Understanding Mathematics Solutions ICSE Class 6.

(iv) 49\dfrac{4}{9}

The figure (square) is divided into 9 equal parts. Shade 4 parts out of 9.

Shade the parts of the following figures according to given fractions: Fractions, ML Aggarwal Understanding Mathematics Solutions ICSE Class 6.

(v) 13\dfrac{1}{3}

The figure (hexagon) is divided into 6 equal parts (i.e., 2 parts make 13\dfrac{1}{3}). Shade 2 parts out of 6.

Shade the parts of the following figures according to given fractions: Fractions, ML Aggarwal Understanding Mathematics Solutions ICSE Class 6.

(vi) 58\dfrac{5}{8}

The figure (8 circles) shows 8 equal parts. Shade 5 circles out of 8.

Shade the parts of the following figures according to given fractions: Fractions, ML Aggarwal Understanding Mathematics Solutions ICSE Class 6.

Question 6

Write the fraction in which

(i) numerator = 5 and denominator = 13

(ii) denominator = 23 and numerator = 17

Answer

(i) numerator = 5 and denominator = 13

Fraction = numeratordenominator=513\dfrac{\text{numerator}}{\text{denominator}} = \dfrac{5}{13}.

Hence, the required fraction = 513\dfrac{5}{13}.

(ii) denominator = 23 and numerator = 17

Fraction = numeratordenominator=1723\dfrac{\text{numerator}}{\text{denominator}} = \dfrac{17}{23}.

Hence, the required fraction = 1723\dfrac{17}{23}.

Question 7

Shabana has to stitch 35 dresses. So far, she has stitched 21 dresses. What fraction of dresses has she stitched?

Answer

Total number of dresses to be stitched = 35

Number of dresses stitched so far = 21

Fraction of dresses stitched = Dresses stitchedTotal dresses\dfrac{\text{Dresses stitched}}{\text{Total dresses}}

= 2135\dfrac{21}{35}

Hence, the required fraction = 2135\dfrac{21}{35}.

Question 8

What fraction of a day is 8 hours?

Answer

We know, 1 day = 24 hours.

Fraction = 8 hours24 hours\dfrac{8 \text{ hours}}{24 \text{ hours}}

= 824\dfrac{8}{24}

Hence, the required fraction = 824\dfrac{8}{24}.

Question 9

What fraction of an hour is 45 minutes?

Answer

We know, 1 hour = 60 minutes.

Fraction = 45 minutes60 minutes\dfrac{45 \text{ minutes}}{60 \text{ minutes}}

= 4560\dfrac{45}{60}

Hence, the required fraction = 4560\dfrac{45}{60}.

Question 10

How many natural numbers are there from 87 to 97? What fraction of them are prime numbers?

Answer

Natural numbers from 87 to 97 are :

87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97 and their number = 11.

Out of these, the prime numbers are 89, 97.

Fraction of prime numbers = Number of primesTotal numbers=211\dfrac{\text{Number of primes}}{\text{Total numbers}} = \dfrac{2}{11}.

Hence, total natural numbers = 11 and fraction of prime numbers = 211\dfrac{2}{11}.

Exercise 6.2

Question 1

Show the fractions 25,35,45\dfrac{2}{5}, \dfrac{3}{5}, \dfrac{4}{5} and 55\dfrac{5}{5} on a number line.

Answer

Draw a straight line and mark a point O on it representing 0. Mark a point A on the right of O at unit length so that OA represents 1.

Now divide the line segment OA into 5 equal parts. Each part represents 15\dfrac{1}{5}.

Starting from O, mark the points at 15,25,35,45\dfrac{1}{5}, \dfrac{2}{5}, \dfrac{3}{5}, \dfrac{4}{5} and 55\dfrac{5}{5} (= 1).

Draw a straight line and mark a point O on it representing 0. Mark a point A on the right of O at unit length so that OA represents 1. Fractions, ML Aggarwal Understanding Mathematics Solutions ICSE Class 6.

Hence, the fractions 25,35,45\dfrac{2}{5}, \dfrac{3}{5}, \dfrac{4}{5} and 55\dfrac{5}{5} are represented on the number line as shown above.

Question 2

Show 18,28,38\dfrac{1}{8}, \dfrac{2}{8}, \dfrac{3}{8} and 78\dfrac{7}{8} on a number line.

Answer

Draw a straight line and mark a point O on it representing 0. Mark a point A on the right of O at unit length so that OA represents 1.

Now divide the line segment OA into 8 equal parts. Each part represents 18\dfrac{1}{8}.

Starting from O, mark the points at 18,28,38\dfrac{1}{8}, \dfrac{2}{8}, \dfrac{3}{8} and 78\dfrac{7}{8}.

Draw a straight line and mark a point O on it representing 0. Mark a point A on the right of O at unit length so that OA represents 1. Fractions, ML Aggarwal Understanding Mathematics Solutions ICSE Class 6.

Hence, the fractions 18,28,38\dfrac{1}{8}, \dfrac{2}{8}, \dfrac{3}{8} and 78\dfrac{7}{8} are represented on the number line as shown above.

Question 3

Show 010,110,310,510,710\dfrac{0}{10}, \dfrac{1}{10}, \dfrac{3}{10}, \dfrac{5}{10}, \dfrac{7}{10} and 1010\dfrac{10}{10} on a number line.

Answer

Draw a straight line and mark a point O on it representing 0. Mark a point A on the right of O at unit length so that OA represents 1.

Now divide the line segment OA into 10 equal parts. Each part represents 110\dfrac{1}{10}.

Starting from O, mark the points at 010\dfrac{0}{10} (= 0), 110,310,510,710\dfrac{1}{10}, \dfrac{3}{10}, \dfrac{5}{10}, \dfrac{7}{10} and 1010\dfrac{10}{10} (= 1).

Draw a straight line and mark a point O on it representing 0. Mark a point A on the right of O at unit length so that OA represents 1. Fractions, ML Aggarwal Understanding Mathematics Solutions ICSE Class 6.

Hence, the fractions 010,110,310,510,710\dfrac{0}{10}, \dfrac{1}{10}, \dfrac{3}{10}, \dfrac{5}{10}, \dfrac{7}{10} and 1010\dfrac{10}{10} are represented on the number line as shown above.

Exercise 6.3

Question 1

State which of the following fractions are proper, improper or mixed:

(i) 1526\dfrac{15}{26}

(ii) 1712\dfrac{17}{12}

(iii) 5235\dfrac{2}{3}

(iv) 68\dfrac{6}{8}

(v) 115711\dfrac{5}{7}

(vi) 1178\dfrac{117}{8}

(vii) 222333\dfrac{222}{333}

(viii) 531247\dfrac{531}{247}

Answer

(i) 1526\dfrac{15}{26}

Here, numerator (15) < denominator (26).

Hence, 1526\dfrac{15}{26} is a proper fraction.

(ii) 1712\dfrac{17}{12}

Here, numerator (17) > denominator (12).

Hence, 1712\dfrac{17}{12} is an improper fraction.

(iii) 5235\dfrac{2}{3}

It consists of a natural number 5 and a proper fraction 23\dfrac{2}{3}.

Hence, 5235\dfrac{2}{3} is a mixed fraction.

(iv) 68\dfrac{6}{8}

Here, numerator (6) < denominator (8).

Hence, 68\dfrac{6}{8} is a proper fraction.

(v) 115711\dfrac{5}{7}

It consists of a natural number 11 and a proper fraction 57\dfrac{5}{7}.

Hence, 115711\dfrac{5}{7} is a mixed fraction.

(vi) 1178\dfrac{117}{8}

Here, numerator (117) > denominator (8).

Hence, 1178\dfrac{117}{8} is an improper fraction.

(vii) 222333\dfrac{222}{333}

Here, numerator (222) < denominator (333).

Hence, 222333\dfrac{222}{333} is a proper fraction.

(viii) 531247\dfrac{531}{247}

Here, numerator (531) > denominator (247).

Hence, 531247\dfrac{531}{247} is an improper fraction.

Question 2

Convert the following improper fractions into mixed numbers:

(i) 173\dfrac{17}{3}

(ii) 11915\dfrac{119}{15}

(iii) 96113\dfrac{961}{13}

(iv) 11732\dfrac{117}{32}

Answer

(i) 173\dfrac{17}{3}

Dividing 17 by 3, we get quotient = 5 and remainder = 2.

173=523.\Rightarrow \dfrac{17}{3} = 5\dfrac{2}{3}.

Hence, 173=523\dfrac{17}{3} = 5\dfrac{2}{3}.

(ii) 11915\dfrac{119}{15}

Dividing 119 by 15, we get quotient = 7 and remainder = 14.

11915=71415.\Rightarrow \dfrac{119}{15} = 7\dfrac{14}{15}.

Hence, 11915=71415\dfrac{119}{15} = 7\dfrac{14}{15}.

(iii) 96113\dfrac{961}{13}

Dividing 961 by 13, we get quotient = 73 and remainder = 12.

96113=731213.\Rightarrow \dfrac{961}{13} = 73\dfrac{12}{13}.

Hence, 96113=731213\dfrac{961}{13} = 73\dfrac{12}{13}.

(iv) 11732\dfrac{117}{32}

Dividing 117 by 32, we get quotient = 3 and remainder = 21.

11732=32132.\Rightarrow \dfrac{117}{32} = 3\dfrac{21}{32}.

Hence, 11732=32132\dfrac{117}{32} = 3\dfrac{21}{32}.

Question 3

Convert the following mixed fractions into improper fractions:

(i) 72117\dfrac{2}{11}

(ii) 35483\dfrac{5}{48}

(iii) 1376413\dfrac{7}{64}

(iv) 7237\dfrac{2}{3}

Answer

We use the rule: improper fraction = (natural number×denominator)+numeratordenominator\dfrac{(\text{natural number} \times \text{denominator}) + \text{numerator}}{\text{denominator}}.

(i) 72117\dfrac{2}{11}

7211=7×11+211=77+211=7911.\Rightarrow 7\dfrac{2}{11} = \dfrac{7 \times 11 + 2}{11} \\[1em] = \dfrac{77 + 2}{11} \\[1em] = \dfrac{79}{11}.

Hence, the required fraction is 7211=79117\dfrac{2}{11} = \dfrac{79}{11}.

(ii) 35483\dfrac{5}{48}

3548=3×48+548=144+548=14948.\Rightarrow 3\dfrac{5}{48} = \dfrac{3 \times 48 + 5}{48} \\[1em] = \dfrac{144 + 5}{48} \\[1em] = \dfrac{149}{48}.

Hence, the required fraction is 3548=149483\dfrac{5}{48} = \dfrac{149}{48}.

(iii) 1376413\dfrac{7}{64}

13764=13×64+764=832+764=83964.\Rightarrow 13\dfrac{7}{64} = \dfrac{13 \times 64 + 7}{64} \\[1em] = \dfrac{832 + 7}{64} \\[1em] = \dfrac{839}{64}.

Hence, the required fraction is 13764=8396413\dfrac{7}{64} = \dfrac{839}{64}.

(iv) 7237\dfrac{2}{3}

723=7×3+23=21+23=233.\Rightarrow 7\dfrac{2}{3} = \dfrac{7 \times 3 + 2}{3} \\[1em] = \dfrac{21 + 2}{3} \\[1em] = \dfrac{23}{3}.

Hence, the required fraction is 723=2337\dfrac{2}{3} = \dfrac{23}{3}.

Question 4

Write the fractions representing the shaded regions and pair up the equivalent fractions from each row:

Write the fractions representing the shaded regions and pair up the equivalent fractions from each row: Fractions, ML Aggarwal Understanding Mathematics Solutions ICSE Class 6.
Write the fractions representing the shaded regions and pair up the equivalent fractions from each row: Fractions, ML Aggarwal Understanding Mathematics Solutions ICSE Class 6.

Answer

The fractions representing the shaded regions are:

(i) Total parts = 2

Shaded parts = 1

Fraction = Shaded partsTotal parts=12\dfrac{\text{Shaded parts}}{\text{Total parts}} = \dfrac{1}{2}.

Hence, fraction = 12\dfrac{1}{2}

(ii) Total parts = 6

Shaded parts = 4

Fraction = Shaded partsTotal parts=46\dfrac{\text{Shaded parts}}{\text{Total parts}} = \dfrac{4}{6}.

Hence, fraction = 46\dfrac{4}{6}

(iii) Total parts = 9

Shaded parts = 3

Fraction = Shaded partsTotal parts=39\dfrac{\text{Shaded parts}}{\text{Total parts}} = \dfrac{3}{9}.

Hence, fraction = 39\dfrac{3}{9}

(iv) Total parts = 8

Shaded parts = 2

Fraction = Shaded partsTotal parts=28\dfrac{\text{Shaded parts}}{\text{Total parts}} = \dfrac{2}{8}.

Hence, fraction = 28\dfrac{2}{8}

(v) Total parts = 4

Shaded parts = 3

Fraction = Shaded partsTotal parts=34\dfrac{\text{Shaded parts}}{\text{Total parts}} = \dfrac{3}{4}.

Hence, fraction = 34\dfrac{3}{4}

(a) Total parts = 8

Shaded parts = 2

Fraction = Shaded partsTotal parts=28\dfrac{\text{Shaded parts}}{\text{Total parts}} = \dfrac{2}{8}.

Hence, fraction = 28\dfrac{2}{8}

(b) Total parts = 12

Shaded parts = 8

Fraction = Shaded partsTotal parts=812\dfrac{\text{Shaded parts}}{\text{Total parts}} = \dfrac{8}{12}.

Hence, fraction = 812\dfrac{8}{12}

(c) Total parts = 16

Shaded parts = 12

Fraction = Shaded partsTotal parts=1216=34\dfrac{\text{Shaded parts}}{\text{Total parts}} = \dfrac{12}{16} = \dfrac{3}{4}.

Hence, fraction = 34\dfrac{3}{4}

(d) Total parts = 8

Shaded parts = 4

Fraction = Shaded partsTotal parts=48\dfrac{\text{Shaded parts}}{\text{Total parts}} = \dfrac{4}{8}.

Hence, fraction = 48\dfrac{4}{8}

(e) Total parts = 9

Shaded parts = 3

Fraction = Shaded partsTotal parts=39\dfrac{\text{Shaded parts}}{\text{Total parts}} = \dfrac{3}{9}.

Hence, fraction = 39\dfrac{3}{9}

Hence, the equivalent pairs are:

(i) ↔ (d), (ii) ↔ (b), (iii) ↔ (e), (iv) ↔ (a), (v) ↔ (c).

Question 5

(i) Find the equivalent fraction of 1535\dfrac{15}{35} with denominator 7

(ii) Find the equivalent fraction of 29\dfrac{2}{9} with denominator 63

Answer

(i) Equivalent fraction of 1535\dfrac{15}{35} with denominator 7

To get 7 from 35, we have to divide 35 by 5.

So, divide both numerator and denominator by 5.

1535=15÷535÷5=37.\Rightarrow \dfrac{15}{35} = \dfrac{15 \div 5}{35 \div 5} \\[1em] = \dfrac{3}{7}.

Hence, the required equivalent fraction = 37\dfrac{3}{7}.

(ii) Equivalent fraction of 29\dfrac{2}{9} with denominator 63

To get 63 from 9, we have to multiply 9 by 7.

So, multiply both numerator and denominator by 7.

29=2×79×7=1463.\Rightarrow \dfrac{2}{9} = \dfrac{2 \times 7}{9 \times 7} \\[1em] = \dfrac{14}{63}.

Hence, the required equivalent fraction = 1463\dfrac{14}{63}.

Question 6

Find the equivalent fraction of 35\dfrac{3}{5} having

(i) denominator 30

(ii) numerator 27

Answer

(i) Equivalent fraction of 35\dfrac{3}{5} with denominator 30

To get 30 from 5, we have to multiply 5 by 6.

So, multiply both numerator and denominator by 6.

35=3×65×6=1830.\Rightarrow \dfrac{3}{5} = \dfrac{3 \times 6}{5 \times 6} \\[1em] = \dfrac{18}{30}.

Hence, the required equivalent fraction = 1830\dfrac{18}{30}.

(ii) Equivalent fraction of 35\dfrac{3}{5} with numerator 27

To get 27 from 3, we have to multiply 3 by 9.

So, multiply both numerator and denominator by 9.

35=3×95×9=2745.\Rightarrow \dfrac{3}{5} = \dfrac{3 \times 9}{5 \times 9} \\[1em] = \dfrac{27}{45}.

Hence, the required equivalent fraction = 2745\dfrac{27}{45}.

Question 7

Replace '653\boxed{\phantom{653}}' in each of the following by the correct number:

(i) 23=65315\dfrac{2}{3} = \dfrac{\boxed{\phantom{653}}}{15}

(ii) 718=42653\dfrac{7}{18} = \dfrac{42}{\boxed{\phantom{653}}}

(iii) 4653=1215\dfrac{4}{\boxed{\phantom{653}}} = \dfrac{12}{15}

(iv) 65311=70154\dfrac{\boxed{\phantom{653}}}{11} = \dfrac{70}{154}

Answer

(i) 23=65315\dfrac{2}{3} = \dfrac{\boxed{\phantom{653}}}{15}

To get 15 from 3, we have to multiply 3 by 5.

So, multiply both numerator and denominator by 5.

23=2×53×5=1015.\Rightarrow \dfrac{2}{3} = \dfrac{2 \times 5}{3 \times 5} \\[1em] = \dfrac{10}{15}.

Hence, replace 653\boxed{\phantom{653}} by 10.

(ii) 718=42653\dfrac{7}{18} = \dfrac{42}{\boxed{\phantom{653}}}

To get 42 from 7, we have to multiply 7 by 6.

So, multiply both numerator and denominator by 6.

718=7×618×6=42108.\Rightarrow \dfrac{7}{18} = \dfrac{7 \times 6}{18 \times 6} \\[1em] = \dfrac{42}{108}.

Hence, replace 653\boxed{\phantom{653}} by 108.

(iii) 4653=1215\dfrac{4}{\boxed{\phantom{653}}} = \dfrac{12}{15}

To get 4 from 12, we have to divide 12 by 3.

So, divide both numerator and denominator by 3.

1215=12÷315÷3=45.\Rightarrow \dfrac{12}{15} = \dfrac{12 \div 3}{15 \div 3} \\[1em] = \dfrac{4}{5}.

Hence, replace 653\boxed{\phantom{653}} by 5.

(iv) 65311=70154\dfrac{\boxed{\phantom{653}}}{11} = \dfrac{70}{154}

To get 11 from 154, we have to divide 154 by 14.

So, divide both numerator and denominator by 14.

70154=70÷14154÷14=511.\Rightarrow \dfrac{70}{154} = \dfrac{70 \div 14}{154 \div 14} \\[1em] = \dfrac{5}{11}.

Hence, replace 653\boxed{\phantom{653}} by 5.

Question 8

Check whether the given pairs of fractions are equivalent:

(i) 310,1240\dfrac{3}{10}, \dfrac{12}{40}

(ii) 58,3048\dfrac{5}{8}, \dfrac{30}{48}

(iii) 46,3020\dfrac{4}{6}, \dfrac{30}{20}

(iv) 713,511\dfrac{7}{13}, \dfrac{5}{11}

Answer

(i) 310,1240\dfrac{3}{10}, \dfrac{12}{40}

By cross multiplication,

3 × 40 = 120 and 10 × 12 = 120

Here, the cross products are equal.

Hence, 310\dfrac{3}{10} and 1240\dfrac{12}{40} are equivalent fractions.

(ii) 58,3048\dfrac{5}{8}, \dfrac{30}{48}

By cross multiplication,

5 × 48 = 240 and 8 × 30 = 240

Here, the cross products are equal.

Hence, 58\dfrac{5}{8} and 3048\dfrac{30}{48} are equivalent fractions.

(iii) 46,3020\dfrac{4}{6}, \dfrac{30}{20}

By cross multiplication,

4 × 20 = 80 and 6 × 30 = 180

Here, the cross products are not equal.

Hence, 46\dfrac{4}{6} and 3020\dfrac{30}{20} are not equivalent fractions.

(iv) 713,511\dfrac{7}{13}, \dfrac{5}{11}

By cross multiplication,

7 × 11 = 77 and 13 × 5 = 65

Here, the cross products are not equal.

Hence, 713\dfrac{7}{13} and 511\dfrac{5}{11} are not equivalent fractions.

Question 9

Reduce the following fractions to simplest form:

(i) 1227\dfrac{12}{27}

(ii) 150350\dfrac{150}{350}

(iii) 1881\dfrac{18}{81}

(iv) 276115\dfrac{276}{115}

Answer

(i) 1227\dfrac{12}{27}

By prime factorisation,

1227=2×2×33×3×3=2×23×3=49.\Rightarrow \dfrac{12}{27} = \dfrac{2 \times 2 \times 3}{3 \times 3 \times 3} \\[1em] = \dfrac{2 \times 2}{3 \times 3} \\[1em] = \dfrac{4}{9}.

Hence, 1227\dfrac{12}{27} in simplest form is 49\dfrac{4}{9}.

(ii) 150350\dfrac{150}{350}

By prime factorisation,

150350=2×3×5×52×5×5×7=37.\Rightarrow \dfrac{150}{350} = \dfrac{2 \times 3 \times 5 \times 5}{2 \times 5 \times 5 \times 7} \\[1em] = \dfrac{3}{7}.

Hence, 150350\dfrac{150}{350} in simplest form is 37\dfrac{3}{7}.

(iii) 1881\dfrac{18}{81}

By prime factorisation,

1881=2×3×33×3×3×3=23×3=29.\Rightarrow \dfrac{18}{81} = \dfrac{2 \times 3 \times 3}{3 \times 3 \times 3 \times 3} \\[1em] = \dfrac{2}{3 \times 3} \\[1em] = \dfrac{2}{9}.

Hence, 1881\dfrac{18}{81} in simplest form is 29\dfrac{2}{9}.

(iv) 276115\dfrac{276}{115}

By prime factorisation,

276115=2×2×3×235×23=2×2×35=125=225.\Rightarrow \dfrac{276}{115} = \dfrac{2 \times 2 \times 3 \times 23}{5 \times 23} \\[1em] = \dfrac{2 \times 2 \times 3}{5} \\[1em] = \dfrac{12}{5} \\[1em] = 2\dfrac{2}{5}.

Hence, 276115\dfrac{276}{115} in simplest form is 125\dfrac{12}{5} or 2252\dfrac{2}{5}.

Question 10

Convert the following fractions into equivalent like fractions:

(i) 78,514\dfrac{7}{8}, \dfrac{5}{14}

(ii) 56,716\dfrac{5}{6}, \dfrac{7}{16}

(iii) 34,56,78\dfrac{3}{4}, \dfrac{5}{6}, \dfrac{7}{8}

Answer

(i) 78,514\dfrac{7}{8}, \dfrac{5}{14}

L.C.M. of 8 and 14 is :

28, 14
24, 7
22, 7
71, 7
1, 1

LCM of 8 and 14 = 2 x 2 x 2 x 7 = 56

78=7×78×7=4956514=5×414×4=2056\Rightarrow \dfrac{7}{8} = \dfrac{7 \times 7}{8 \times 7} = \dfrac{49}{56} \\[1em] \Rightarrow \dfrac{5}{14} = \dfrac{5 \times 4}{14 \times 4} = \dfrac{20}{56}

Hence, the equivalent like fractions are 4956\dfrac{49}{56} and 2056\dfrac{20}{56}.

(ii) 56,716\dfrac{5}{6}, \dfrac{7}{16}

L.C.M. of 6 and 16 is :

26, 16
23, 8
23, 4
23, 2
33, 1
1, 1

LCM of 6 and 16 = 2 x 2 x 2 x 2 x 3 = 48.

56=5×86×8=4048716=7×316×3=2148\Rightarrow \dfrac{5}{6} = \dfrac{5 \times 8}{6 \times 8} = \dfrac{40}{48} \\[1em] \Rightarrow \dfrac{7}{16} = \dfrac{7 \times 3}{16 \times 3} = \dfrac{21}{48}

Hence, the equivalent like fractions are 4048\dfrac{40}{48} and 2148\dfrac{21}{48}.

(iii) 34,56,78\dfrac{3}{4}, \dfrac{5}{6}, \dfrac{7}{8}

L.C.M. of 4, 6 and 8 is :

24, 6, 8
22, 3, 4
21, 3, 2
31, 3, 1
1, 1, 1

LCM of 4, 6 and 8 = 2 x 2 x 2 x 3 = 24.

34=3×64×6=182456=5×46×4=202478=7×38×3=2124\Rightarrow \dfrac{3}{4} = \dfrac{3 \times 6}{4 \times 6} = \dfrac{18}{24} \\[1em] \Rightarrow \dfrac{5}{6} = \dfrac{5 \times 4}{6 \times 4} = \dfrac{20}{24} \\[1em] \Rightarrow \dfrac{7}{8} = \dfrac{7 \times 3}{8 \times 3} = \dfrac{21}{24}

Hence, the equivalent like fractions are 1824,2024\dfrac{18}{24}, \dfrac{20}{24} and 2124\dfrac{21}{24}.

Question 11

Here, a unit is divided into 5 equal parts. Write the fraction that gives the length of the black bold lines in the respective boxes or in your notebook.

Here, a unit is divided into 5 equal parts. Write the fraction that gives the length of the black bold lines in the respective boxes or in your notebook. Fractions, ML Aggarwal Understanding Mathematics Solutions ICSE Class 6.

Answer

Each unit is divided into 5 equal parts, so each part represents 15\dfrac{1}{5}.

The bold line shown in the figure starts from 0 and goes up to a length of 2 parts, so it represents 25\dfrac{2}{5}.

The remaining boxes are filled as follows (counting parts from 0 to the end of bold line):

The fraction in the first box (after 15\dfrac{1}{5}) = 25\dfrac{2}{5}.

The fraction in the second box (after 35\dfrac{3}{5}) = 45\dfrac{4}{5}.

The fraction in the third box (after 1) = 65\dfrac{6}{5} or 1151\dfrac{1}{5}.

Hence, the missing fractions are 25,45\dfrac{2}{5}, \dfrac{4}{5} and 65\dfrac{6}{5} (i.e. 1151\dfrac{1}{5}).

Question 12

Find the missing numbers:

(i) 3 glasses of juice shared equally among 4 friends is the same as _____ glasses of juice shared equally among 8 friends.

So, 34=6538\dfrac{3}{4} = \dfrac{\boxed{\phantom{653}}}{8}

(ii) 4 kg of sugar divided equally in 3 bags is the same as 12 kg of sugar divided equally in _____ bags.

So, 43=12653\dfrac{4}{3} = \dfrac{12}{\boxed{\phantom{653}}}

(iii) 7 gulabjamuns divided among 5 children is the same as _____ gulabjamuns divided among _____ children.

So, 75=653653\dfrac{7}{5} = \dfrac{\boxed{\phantom{653}}}{\boxed{\phantom{653}}}

Answer

(i) 34=6538\dfrac{3}{4} = \dfrac{\boxed{\phantom{653}}}{8}

To get 8 from 4, we have to multiply 4 by 2.

So, multiply numerator and denominator by 2.

34=3×24×2=68.\Rightarrow \dfrac{3}{4} = \dfrac{3 \times 2}{4 \times 2} = \dfrac{6}{8}.

Hence, the missing number is 6 i.e. 6 glasses of juice shared equally among 8 friends.

(ii) 43=12653\dfrac{4}{3} = \dfrac{12}{\boxed{\phantom{653}}}

To get 12 from 4, we have to multiply 4 by 3.

So, multiply numerator and denominator by 3.

43=4×33×3=129.\Rightarrow \dfrac{4}{3} = \dfrac{4 \times 3}{3 \times 3} = \dfrac{12}{9}.

Hence, the missing number is 9 i.e. 12 kg of sugar divided equally in 9 bags.

(iii) 75=653653\dfrac{7}{5} = \dfrac{\boxed{\phantom{653}}}{\boxed{\phantom{653}}}

We can multiply both numerator and denominator by 2.

75=7×25×2=1410.\Rightarrow \dfrac{7}{5} = \dfrac{7 \times 2}{5 \times 2} = \dfrac{14}{10}.

Hence, the missing numbers are 14 and 10 i.e. 14 gulabjamuns divided among 10 children.

Question 13

Raghu got a job at the age of 24 years and got retired from the job at the age of 60 years. What fraction of his age till retirement was he in job?

Answer

Age at which Raghu got the job = 24 years.

Age of retirement = 60 years.

Number of years he was in job = 60 - 24 = 36 years.

Total age till retirement = 60 years.

Fraction of his age in job = Years in jobTotal age\dfrac{\text{Years in job}}{\text{Total age}}

=3660=35.= \dfrac{36}{60} \\[1em] = \dfrac{3}{5}.

Hence, the required fraction = 35\dfrac{3}{5}.

Exercise 6.4

Question 1

Compare the given fractions and replace '653\boxed{\phantom{653}}' by an appropriate sign '< or >':

(i) 3665356\dfrac{3}{6} \boxed{\phantom{653}} \dfrac{5}{6}

(ii) 2765325\dfrac{2}{7} \boxed{\phantom{653}} \dfrac{2}{5}

(iii) 3565345\dfrac{3}{5} \boxed{\phantom{653}} \dfrac{4}{5}

(iv) 4765349\dfrac{4}{7} \boxed{\phantom{653}} \dfrac{4}{9}

Answer

(i) 36\dfrac{3}{6} and 56\dfrac{5}{6}

These are like fractions (same denominator 6).

In like fractions, the fraction with greater numerator is greater.

Since 3 < 5, therefore, 36<56\dfrac{3}{6} \lt \dfrac{5}{6}.

Hence, 36<56\dfrac{3}{6} \lt \dfrac{5}{6}.

(ii) 27\dfrac{2}{7} and 25\dfrac{2}{5}

These are unlike fractions with same numerator 2.

In fractions with same numerator, the fraction with smaller denominator is greater.

Since 7 > 5, therefore, 27<25\dfrac{2}{7} \lt \dfrac{2}{5}.

Hence, 27<25\dfrac{2}{7} \lt \dfrac{2}{5}.

(iii) 35\dfrac{3}{5} and 45\dfrac{4}{5}

These are like fractions (same denominator 5).

In like fractions, the fraction with greater numerator is greater.

Since 3 < 4, therefore, 35<45\dfrac{3}{5} \lt \dfrac{4}{5}.

Hence, 35<45\dfrac{3}{5} \lt \dfrac{4}{5}.

(iv) 47\dfrac{4}{7} and 49\dfrac{4}{9}

These are unlike fractions with same numerator 4.

In fractions with same numerator, the fraction with smaller denominator is greater.

Since 7 < 9, therefore, 47>49\dfrac{4}{7} \gt \dfrac{4}{9}.

Hence, 47>49\dfrac{4}{7} \gt \dfrac{4}{9}.

Question 2

Replace '653\boxed{\phantom{653}}' by an appropriate sign '< , = or >' between the given fractions:

(i) 1265315\dfrac{1}{2} \boxed{\phantom{653}} \dfrac{1}{5}

(ii) 2465336\dfrac{2}{4} \boxed{\phantom{653}} \dfrac{3}{6}

(iii) 7965339\dfrac{7}{9} \boxed{\phantom{653}} \dfrac{3}{9}

(iv) 3465328\dfrac{3}{4} \boxed{\phantom{653}} \dfrac{2}{8}

Answer

(i) 12\dfrac{1}{2} and 15\dfrac{1}{5}

These are unlike fractions with same numerator 1.

In fractions with same numerator, the fraction with smaller denominator is greater.

Since 2 < 5, therefore, 12>15\dfrac{1}{2} \gt \dfrac{1}{5}.

Hence, 12>15\dfrac{1}{2} \gt \dfrac{1}{5}.

(ii) 24\dfrac{2}{4} and 36\dfrac{3}{6}

By cross multiplication,

2 × 6 = 12 and 4 × 3 = 12

The cross products are equal.

Hence, 24=36\dfrac{2}{4} = \dfrac{3}{6}.

(iii) 79\dfrac{7}{9} and 39\dfrac{3}{9}

These are like fractions (same denominator 9).

In like fractions, the fraction with greater numerator is greater.

Since 7 > 3, therefore, 79>39\dfrac{7}{9} \gt \dfrac{3}{9}.

Hence, 79>39\dfrac{7}{9} \gt \dfrac{3}{9}.

(iv) 34\dfrac{3}{4} and 28\dfrac{2}{8}

By cross multiplication,

3 × 8 = 24 and 4 × 2 = 8

Since 24 > 8, therefore, 34>28\dfrac{3}{4} \gt \dfrac{2}{8}.

Hence, 34>28\dfrac{3}{4} \gt \dfrac{2}{8}.

Question 3

Compare the following pairs of fractions:

(i) 59\dfrac{5}{9} and 45\dfrac{4}{5}

(ii) 916\dfrac{9}{16} and 59\dfrac{5}{9}

Answer

(i) 59\dfrac{5}{9} and 45\dfrac{4}{5}

LCM of 9 and 5 = 45.

Write the given fractions as equivalent like fractions.

59=5×59×5=254545=4×95×9=3645\Rightarrow \dfrac{5}{9} = \dfrac{5 \times 5}{9 \times 5} = \dfrac{25}{45} \\[1em] \Rightarrow \dfrac{4}{5} = \dfrac{4 \times 9}{5 \times 9} = \dfrac{36}{45}

As 25 < 36, 2545<364559<45\dfrac{25}{45} \lt \dfrac{36}{45} \Rightarrow \dfrac{5}{9} \lt \dfrac{4}{5}.

Hence, 59<45\dfrac{5}{9} \lt \dfrac{4}{5}.

(ii) 916\dfrac{9}{16} and 59\dfrac{5}{9}

LCM of 16 and 9 = 144.

Write the given fractions as equivalent like fractions.

916=9×916×9=8114459=5×169×16=80144\Rightarrow \dfrac{9}{16} = \dfrac{9 \times 9}{16 \times 9} = \dfrac{81}{144} \\[1em] \Rightarrow \dfrac{5}{9} = \dfrac{5 \times 16}{9 \times 16} = \dfrac{80}{144}

As 81 > 80, 81144>80144916>59\dfrac{81}{144} \gt \dfrac{80}{144} \Rightarrow \dfrac{9}{16} \gt \dfrac{5}{9}.

Hence, 916>59\dfrac{9}{16} \gt \dfrac{5}{9}.

Question 4

Fill in the boxes by the symbol < or > to make the given statements true:

(i) 51165337\dfrac{5}{11} \boxed{\phantom{653}} \dfrac{3}{7}

(ii) 815\dfrac{8}{15} 653\boxed{\phantom{653}} 35\dfrac{3}{5}

(iii) 1114\dfrac{11}{14} 653\boxed{\phantom{653}} 2935\dfrac{29}{35}

(iv) 1327\dfrac{13}{27} 653\boxed{\phantom{653}} 1548\dfrac{15}{48}

Answer

(i) 511\dfrac{5}{11} and 37\dfrac{3}{7}

By cross multiplication,

5 × 7 = 35 and 11 × 3 = 33

Since 35 > 33, therefore, 511>37\dfrac{5}{11} \gt \dfrac{3}{7}.

Hence, 511>37\dfrac{5}{11} \gt \dfrac{3}{7}.

(ii) 815\dfrac{8}{15} and 35\dfrac{3}{5}

By cross multiplication,

8 × 5 = 40 and 15 × 3 = 45

Since 40 < 45, therefore, 815<35\dfrac{8}{15} \lt \dfrac{3}{5}.

Hence, 815<35\dfrac{8}{15} \lt \dfrac{3}{5}.

(iii) 1114\dfrac{11}{14} and 2935\dfrac{29}{35}

LCM of 14 and 35 = 70.

1114=11×514×5=55702935=29×235×2=5870\Rightarrow \dfrac{11}{14} = \dfrac{11 \times 5}{14 \times 5} = \dfrac{55}{70} \\[1em] \Rightarrow \dfrac{29}{35} = \dfrac{29 \times 2}{35 \times 2} = \dfrac{58}{70}

As 55 < 58,

5570<58701114<2935\dfrac{55}{70} \lt \dfrac{58}{70} \Rightarrow \dfrac{11}{14} \lt \dfrac{29}{35}.

Hence, 1114<2935\dfrac{11}{14} \lt \dfrac{29}{35}.

(iv) 1327\dfrac{13}{27} and 1548\dfrac{15}{48}

By cross multiplication,

13 × 48 = 624 and 27 × 15 = 405

Since 624 > 405, therefore, 1327>1548\dfrac{13}{27} \gt \dfrac{15}{48}.

Hence, 1327>1548\dfrac{13}{27} \gt \dfrac{15}{48}.

Question 5

Arrange the given fractions in descending order:

(i) 517,49,712\dfrac{5}{17}, \dfrac{4}{9}, \dfrac{7}{12}

(ii) 712,1136,3772\dfrac{7}{12}, \dfrac{11}{36}, \dfrac{37}{72}

Answer

(i) 517,49,712\dfrac{5}{17}, \dfrac{4}{9}, \dfrac{7}{12}

LCM of 17, 9 and 12 = 612.

Write the given fractions as equivalent like fractions.

517=5×3617×36=18061249=4×689×68=272612712=7×5112×51=357612\Rightarrow \dfrac{5}{17} = \dfrac{5 \times 36}{17 \times 36} = \dfrac{180}{612} \\[1em] \Rightarrow \dfrac{4}{9} = \dfrac{4 \times 68}{9 \times 68} = \dfrac{272}{612} \\[1em] \Rightarrow \dfrac{7}{12} = \dfrac{7 \times 51}{12 \times 51} = \dfrac{357}{612}

As 357 > 272 > 180,

357612>272612>180612712>49>517\dfrac{357}{612} \gt \dfrac{272}{612} \gt \dfrac{180}{612} \Rightarrow \dfrac{7}{12} \gt \dfrac{4}{9} \gt \dfrac{5}{17}.

Hence, the given fractions in descending order are 712,49,517\dfrac{7}{12}, \dfrac{4}{9}, \dfrac{5}{17}.

(ii) 712,1136,3772\dfrac{7}{12}, \dfrac{11}{36}, \dfrac{37}{72}

LCM of 12, 36 and 72 = 72.

Write the given fractions as equivalent like fractions.

712=7×612×6=42721136=11×236×2=22723772=3772\Rightarrow \dfrac{7}{12} = \dfrac{7 \times 6}{12 \times 6} = \dfrac{42}{72} \\[1em] \Rightarrow \dfrac{11}{36} = \dfrac{11 \times 2}{36 \times 2} = \dfrac{22}{72} \\[1em] \Rightarrow \dfrac{37}{72} = \dfrac{37}{72}

As 42 > 37 > 22,

4272>3772>2272712>3772>1136\dfrac{42}{72} \gt \dfrac{37}{72} \gt \dfrac{22}{72} \Rightarrow \dfrac{7}{12} \gt \dfrac{37}{72} \gt \dfrac{11}{36}.

Hence, the given fractions in descending order are 712,3772,1136\dfrac{7}{12}, \dfrac{37}{72}, \dfrac{11}{36}.

Question 6

Arrange the given fractions in ascending order:

(i) 78,1516,56\dfrac{7}{8}, \dfrac{15}{16}, \dfrac{5}{6}

(ii) 34,1522,2633\dfrac{3}{4}, \dfrac{15}{22}, \dfrac{26}{33}

(iii) 512,14,78,56\dfrac{5}{12}, \dfrac{1}{4}, \dfrac{7}{8}, \dfrac{5}{6}

Answer

(i) 78,1516,56\dfrac{7}{8}, \dfrac{15}{16}, \dfrac{5}{6}

LCM of 8, 16 and 6 = 48.

Write the given fractions as equivalent like fractions.

78=7×68×6=42481516=15×316×3=454856=5×86×8=4048\Rightarrow \dfrac{7}{8} = \dfrac{7 \times 6}{8 \times 6} = \dfrac{42}{48} \\[1em] \Rightarrow \dfrac{15}{16} = \dfrac{15 \times 3}{16 \times 3} = \dfrac{45}{48} \\[1em] \Rightarrow \dfrac{5}{6} = \dfrac{5 \times 8}{6 \times 8} = \dfrac{40}{48}

As 40 < 42 < 45,

4048<4248<454856<78<1516\dfrac{40}{48} \lt \dfrac{42}{48} \lt \dfrac{45}{48} \Rightarrow \dfrac{5}{6} \lt \dfrac{7}{8} \lt \dfrac{15}{16}.

Hence, the given fractions in ascending order are 56,78,1516\dfrac{5}{6}, \dfrac{7}{8}, \dfrac{15}{16}.

(ii) 34,1522,2633\dfrac{3}{4}, \dfrac{15}{22}, \dfrac{26}{33}

LCM of 4, 22 and 33 = 132.

Write the given fractions as equivalent like fractions.

34=3×334×33=991321522=15×622×6=901322633=26×433×4=104132\Rightarrow \dfrac{3}{4} = \dfrac{3 \times 33}{4 \times 33} = \dfrac{99}{132} \\[1em] \Rightarrow \dfrac{15}{22} = \dfrac{15 \times 6}{22 \times 6} = \dfrac{90}{132} \\[1em] \Rightarrow \dfrac{26}{33} = \dfrac{26 \times 4}{33 \times 4} = \dfrac{104}{132}

As 90 < 99 < 104,

90132<99132<1041321522<34<2633\dfrac{90}{132} \lt \dfrac{99}{132} \lt \dfrac{104}{132} \Rightarrow \dfrac{15}{22} \lt \dfrac{3}{4} \lt \dfrac{26}{33}.

Hence, the given fractions in ascending order are 1522,34,2633\dfrac{15}{22}, \dfrac{3}{4}, \dfrac{26}{33}.

(iii) 512,14,78,56\dfrac{5}{12}, \dfrac{1}{4}, \dfrac{7}{8}, \dfrac{5}{6}

LCM of 12, 4, 8 and 6 = 24.

Write the given fractions as equivalent like fractions.

512=5×212×2=102414=1×64×6=62478=7×38×3=212456=5×46×4=2024\Rightarrow \dfrac{5}{12} = \dfrac{5 \times 2}{12 \times 2} = \dfrac{10}{24} \\[1em] \Rightarrow \dfrac{1}{4} = \dfrac{1 \times 6}{4 \times 6} = \dfrac{6}{24} \\[1em] \Rightarrow \dfrac{7}{8} = \dfrac{7 \times 3}{8 \times 3} = \dfrac{21}{24} \\[1em] \Rightarrow \dfrac{5}{6} = \dfrac{5 \times 4}{6 \times 4} = \dfrac{20}{24}

As 6 < 10 < 20 < 21,

624<1024<2024<212414<512<56<78\dfrac{6}{24} \lt \dfrac{10}{24} \lt \dfrac{20}{24} \lt \dfrac{21}{24} \Rightarrow \dfrac{1}{4} \lt \dfrac{5}{12} \lt \dfrac{5}{6} \lt \dfrac{7}{8}.

Hence, the given fractions in ascending order are 14,512,56,78\dfrac{1}{4}, \dfrac{5}{12}, \dfrac{5}{6}, \dfrac{7}{8}.

Exercise 6.5

Question 1

Calculate the following:

(i) 815+315\dfrac{8}{15} + \dfrac{3}{15}

(ii) 1215715\dfrac{12}{15} - \dfrac{7}{15}

(iii) 1231 - \dfrac{2}{3}

(iv) 713+213513\dfrac{7}{13} + \dfrac{2}{13} - \dfrac{5}{13}

(v) 245+3352\dfrac{4}{5} + 3\dfrac{3}{5}

(vi) 3271473\dfrac{2}{7} - 1\dfrac{4}{7}

Answer

(i) 815+315\dfrac{8}{15} + \dfrac{3}{15}

8+3151115\Rightarrow \dfrac{8 + 3}{15}\\[1em] \Rightarrow \dfrac{11}{15}

Hence, 815+315=1115\dfrac{8}{15} + \dfrac{3}{15} = \dfrac{11}{15}.

(ii) 1215715\dfrac{12}{15} - \dfrac{7}{15}

1271551513\Rightarrow \dfrac{12 - 7}{15}\\[1em] \Rightarrow \dfrac{5}{15}\\[1em] \Rightarrow \dfrac{1}{3}

Hence, 1215715=13\dfrac{12}{15} - \dfrac{7}{15} = \dfrac{1}{3}.

(iii) 1231 - \dfrac{2}{3}

332332313\Rightarrow \dfrac{3}{3} - \dfrac{2}{3}\\[1em] \Rightarrow \dfrac{3 - 2}{3}\\[1em] \Rightarrow \dfrac{1}{3}

Hence, 123=131 - \dfrac{2}{3} = \dfrac{1}{3}.

(iv) 713+213513\dfrac{7}{13} + \dfrac{2}{13} - \dfrac{5}{13}

7+2513413\Rightarrow \dfrac{7 + 2 - 5}{13}\\[1em] \Rightarrow \dfrac{4}{13}

Hence, 713+213513=413\dfrac{7}{13} + \dfrac{2}{13} - \dfrac{5}{13} = \dfrac{4}{13}.

(v) 245+3352\dfrac{4}{5} + 3\dfrac{3}{5}

145+18514+185325625\Rightarrow \dfrac{14}{5} + \dfrac{18}{5}\\[1em] \Rightarrow \dfrac{14 + 18}{5}\\[1em] \Rightarrow \dfrac{32}{5}\\[1em] \Rightarrow 6\dfrac{2}{5}

Hence, 245+335=6252\dfrac{4}{5} + 3\dfrac{3}{5} = 6\dfrac{2}{5}.

(vi) 3271473\dfrac{2}{7} - 1\dfrac{4}{7}

23711723117127157\Rightarrow \dfrac{23}{7} - \dfrac{11}{7}\\[1em] \Rightarrow \dfrac{23 - 11}{7}\\[1em] \Rightarrow \dfrac{12}{7}\\[1em] \Rightarrow 1\dfrac{5}{7}

Hence, 327147=1573\dfrac{2}{7} - 1\dfrac{4}{7} = 1\dfrac{5}{7}.

Question 2

Calculate the following:

(i) 23+34\dfrac{2}{3} + \dfrac{3}{4}

(ii) 5749\dfrac{5}{7} - \dfrac{4}{9}

(iii) 12+35\dfrac{1}{2} + \dfrac{3}{5}

(iv) 149+35121\dfrac{4}{9} + 3\dfrac{5}{12}

(v) 21417102\dfrac{1}{4} - 1\dfrac{7}{10}

(vi) 35627153\dfrac{5}{6} - 2\dfrac{7}{15}

Answer

(i) 23+34\dfrac{2}{3} + \dfrac{3}{4}

LCM of 3 and 4 = 12.

2×43×4+3×34×3812+9128+91217121512\Rightarrow \dfrac{2 \times 4}{3 \times 4} + \dfrac{3 \times 3}{4 \times 3}\\[1em] \Rightarrow \dfrac{8}{12} + \dfrac{9}{12}\\[1em] \Rightarrow \dfrac{8 + 9}{12}\\[1em] \Rightarrow \dfrac{17}{12}\\[1em] \Rightarrow 1\dfrac{5}{12}

Hence, 23+34=1512\dfrac{2}{3} + \dfrac{3}{4} = 1\dfrac{5}{12}.

(ii) 5749\dfrac{5}{7} - \dfrac{4}{9}

LCM of 7 and 9 = 63.

5×97×94×79×7456328634528631763\Rightarrow \dfrac{5 \times 9}{7 \times 9} - \dfrac{4 \times 7}{9 \times 7}\\[1em] \Rightarrow \dfrac{45}{63} - \dfrac{28}{63}\\[1em] \Rightarrow \dfrac{45 - 28}{63}\\[1em] \Rightarrow \dfrac{17}{63}

Hence, 5749=1763\dfrac{5}{7} - \dfrac{4}{9} = \dfrac{17}{63}.

(iii) 12+35\dfrac{1}{2} + \dfrac{3}{5}

LCM of 2 and 5 = 10.

1×52×5+3×25×2510+6105+61011101110\Rightarrow \dfrac{1 \times 5}{2 \times 5} + \dfrac{3 \times 2}{5 \times 2}\\[1em] \Rightarrow \dfrac{5}{10} + \dfrac{6}{10}\\[1em] \Rightarrow \dfrac{5 + 6}{10}\\[1em] \Rightarrow \dfrac{11}{10}\\[1em] \Rightarrow 1\dfrac{1}{10}

Hence, 12+35=1110\dfrac{1}{2} + \dfrac{3}{5} = 1\dfrac{1}{10}.

(iv) 149+35121\dfrac{4}{9} + 3\dfrac{5}{12}

LCM of 9 and 12 = 36.

139+411213×49×4+41×312×35236+1233652+123361753643136\Rightarrow \dfrac{13}{9} + \dfrac{41}{12}\\[1em] \Rightarrow \dfrac{13 \times 4}{9 \times 4} + \dfrac{41 \times 3}{12 \times 3}\\[1em] \Rightarrow \dfrac{52}{36} + \dfrac{123}{36}\\[1em] \Rightarrow \dfrac{52 + 123}{36}\\[1em] \Rightarrow \dfrac{175}{36}\\[1em] \Rightarrow 4\dfrac{31}{36}

Hence, 149+3512=431361\dfrac{4}{9} + 3\dfrac{5}{12} = 4\dfrac{31}{36}.

(v) 21417102\dfrac{1}{4} - 1\dfrac{7}{10}

LCM of 4 and 10 = 20.

9417109×54×517×210×2452034204534201120\Rightarrow \dfrac{9}{4} - \dfrac{17}{10}\\[1em] \Rightarrow \dfrac{9 \times 5}{4 \times 5} - \dfrac{17 \times 2}{10 \times 2}\\[1em] \Rightarrow \dfrac{45}{20} - \dfrac{34}{20}\\[1em] \Rightarrow \dfrac{45 - 34}{20}\\[1em] \Rightarrow \dfrac{11}{20}

Hence, 2141710=11202\dfrac{1}{4} - 1\dfrac{7}{10} = \dfrac{11}{20}.

(vi) 35627153\dfrac{5}{6} - 2\dfrac{7}{15}

LCM of 6 and 15 = 30.

236371523×56×537×215×21153074301157430413011130\Rightarrow \dfrac{23}{6} - \dfrac{37}{15}\\[1em] \Rightarrow \dfrac{23 \times 5}{6 \times 5} - \dfrac{37 \times 2}{15 \times 2}\\[1em] \Rightarrow \dfrac{115}{30} - \dfrac{74}{30}\\[1em] \Rightarrow \dfrac{115 - 74}{30}\\[1em] \Rightarrow \dfrac{41}{30}\\[1em] \Rightarrow 1\dfrac{11}{30}

Hence, 3562715=111303\dfrac{5}{6} - 2\dfrac{7}{15} = 1\dfrac{11}{30}.

Question 3

Simplify the following:

(i) 123+212+341\dfrac{2}{3} + 2\dfrac{1}{2} + \dfrac{3}{4}

(ii) 329+213+27123\dfrac{2}{9} + 2\dfrac{1}{3} + 2\dfrac{7}{12}

(iii) 712+8956\dfrac{7}{12} + \dfrac{8}{9} - \dfrac{5}{6}

(iv) 1325+720251\dfrac{3}{25} + \dfrac{7}{20} - \dfrac{2}{5}

(v) 11314256+1671\dfrac{13}{14} - 2\dfrac{5}{6} + 1\dfrac{6}{7}

(vi) 31167153 - 1\dfrac{1}{6} - \dfrac{7}{15}

Answer

(i) 123+212+341\dfrac{2}{3} + 2\dfrac{1}{2} + \dfrac{3}{4}

LCM of 3, 2 and 4 = 12.

53+52+345×43×4+5×62×6+3×34×32012+3012+91220+30+912591241112\Rightarrow \dfrac{5}{3} + \dfrac{5}{2} + \dfrac{3}{4}\\[1em] \Rightarrow \dfrac{5 \times 4}{3 \times 4} + \dfrac{5 \times 6}{2 \times 6} + \dfrac{3 \times 3}{4 \times 3}\\[1em] \Rightarrow \dfrac{20}{12} + \dfrac{30}{12} + \dfrac{9}{12}\\[1em] \Rightarrow \dfrac{20 + 30 + 9}{12}\\[1em] \Rightarrow \dfrac{59}{12}\\[1em] \Rightarrow 4\dfrac{11}{12}

Hence, 123+212+34=411121\dfrac{2}{3} + 2\dfrac{1}{2} + \dfrac{3}{4} = 4\dfrac{11}{12}.

(ii) 329+213+27123\dfrac{2}{9} + 2\dfrac{1}{3} + 2\dfrac{7}{12}

LCM of 9, 3 and 12 = 36.

299+73+311229×49×4+7×123×12+31×312×311636+8436+9336116+84+9336293368536\Rightarrow \dfrac{29}{9} + \dfrac{7}{3} + \dfrac{31}{12}\\[1em] \Rightarrow \dfrac{29 \times 4}{9 \times 4} + \dfrac{7 \times 12}{3 \times 12} + \dfrac{31 \times 3}{12 \times 3}\\[1em] \Rightarrow \dfrac{116}{36} + \dfrac{84}{36} + \dfrac{93}{36}\\[1em] \Rightarrow \dfrac{116 + 84 + 93}{36}\\[1em] \Rightarrow \dfrac{293}{36}\\[1em] \Rightarrow 8\dfrac{5}{36}

Hence, 329+213+2712=85363\dfrac{2}{9} + 2\dfrac{1}{3} + 2\dfrac{7}{12} = 8\dfrac{5}{36}.

(iii) 712+8956\dfrac{7}{12} + \dfrac{8}{9} - \dfrac{5}{6}

LCM of 12, 9 and 6 = 36.

7×312×3+8×49×45×66×62136+3236303621+3230362336\Rightarrow \dfrac{7 \times 3}{12 \times 3} + \dfrac{8 \times 4}{9 \times 4} - \dfrac{5 \times 6}{6 \times 6}\\[1em] \Rightarrow \dfrac{21}{36} + \dfrac{32}{36} - \dfrac{30}{36}\\[1em] \Rightarrow \dfrac{21 + 32 - 30}{36}\\[1em] \Rightarrow \dfrac{23}{36}

Hence, 712+8956=2336\dfrac{7}{12} + \dfrac{8}{9} - \dfrac{5}{6} = \dfrac{23}{36}.

(iv) 1325+720251\dfrac{3}{25} + \dfrac{7}{20} - \dfrac{2}{5}

LCM of 25, 20 and 5 = 100.

2825+7202528×425×4+7×520×52×205×20112100+3510040100112+354010010710017100\Rightarrow \dfrac{28}{25} + \dfrac{7}{20} - \dfrac{2}{5}\\[1em] \Rightarrow \dfrac{28 \times 4}{25 \times 4} + \dfrac{7 \times 5}{20 \times 5} - \dfrac{2 \times 20}{5 \times 20}\\[1em] \Rightarrow \dfrac{112}{100} + \dfrac{35}{100} - \dfrac{40}{100}\\[1em] \Rightarrow \dfrac{112 + 35 - 40}{100}\\[1em] \Rightarrow \dfrac{107}{100}\\[1em] \Rightarrow 1\dfrac{7}{100}

Hence, 1325+72025=171001\dfrac{3}{25} + \dfrac{7}{20} - \dfrac{2}{5} = 1\dfrac{7}{100}.

(v) 11314256+1671\dfrac{13}{14} - 2\dfrac{5}{6} + 1\dfrac{6}{7}

LCM of 14, 6 and 7 = 42.

2714176+13727×314×317×76×7+13×67×6814211942+784281119+784240422021\Rightarrow \dfrac{27}{14} - \dfrac{17}{6} + \dfrac{13}{7}\\[1em] \Rightarrow \dfrac{27 \times 3}{14 \times 3} - \dfrac{17 \times 7}{6 \times 7} + \dfrac{13 \times 6}{7 \times 6}\\[1em] \Rightarrow \dfrac{81}{42} - \dfrac{119}{42} + \dfrac{78}{42}\\[1em] \Rightarrow \dfrac{81 - 119 + 78}{42}\\[1em] \Rightarrow \dfrac{40}{42}\\[1em] \Rightarrow \dfrac{20}{21}

Hence, 11314256+167=20211\dfrac{13}{14} - 2\dfrac{5}{6} + 1\dfrac{6}{7} = \dfrac{20}{21}.

(vi) 31167153 - 1\dfrac{1}{6} - \dfrac{7}{15}

LCM of 1, 6 and 15 = 30.

31767153×301×307×56×57×215×290303530143090351430413011130\Rightarrow \dfrac{3}{1} - \dfrac{7}{6} - \dfrac{7}{15}\\[1em] \Rightarrow \dfrac{3 \times 30}{1 \times 30} - \dfrac{7 \times 5}{6 \times 5} - \dfrac{7 \times 2}{15 \times 2}\\[1em] \Rightarrow \dfrac{90}{30} - \dfrac{35}{30} - \dfrac{14}{30}\\[1em] \Rightarrow \dfrac{90 - 35 - 14}{30}\\[1em] \Rightarrow \dfrac{41}{30}\\[1em] \Rightarrow 1\dfrac{11}{30}

Hence, 3116715=111303 - 1\dfrac{1}{6} - \dfrac{7}{15} = 1\dfrac{11}{30}.

Question 4

(i) What number should be added to 512\dfrac{5}{12} to get 2382\dfrac{3}{8}?

(ii) What number should be subtracted from 5 to get 15131\dfrac{5}{13}?

Answer

(i) Required number = 2385122\dfrac{3}{8} - \dfrac{5}{12}

LCM of 8 and 12 = 24.

19851219×38×35×212×257241024571024472412324\Rightarrow \dfrac{19}{8} - \dfrac{5}{12}\\[1em] \Rightarrow \dfrac{19 \times 3}{8 \times 3} - \dfrac{5 \times 2}{12 \times 2}\\[1em] \Rightarrow \dfrac{57}{24} - \dfrac{10}{24}\\[1em] \Rightarrow \dfrac{57 - 10}{24}\\[1em] \Rightarrow \dfrac{47}{24}\\[1em] \Rightarrow 1\dfrac{23}{24}

Hence, the required number = 123241\dfrac{23}{24}.

(ii) Required number = 515135 - 1\dfrac{5}{13}

5118135×131×1318136513181365181347133813\Rightarrow \dfrac{5}{1} - \dfrac{18}{13}\\[1em] \Rightarrow \dfrac{5 \times 13}{1 \times 13} - \dfrac{18}{13}\\[1em] \Rightarrow \dfrac{65}{13} - \dfrac{18}{13}\\[1em] \Rightarrow \dfrac{65 - 18}{13}\\[1em] \Rightarrow \dfrac{47}{13}\\[1em] \Rightarrow 3\dfrac{8}{13}

Hence, the required number = 38133\dfrac{8}{13}.

Exercise 6.6

Question 1

Evaluate the following:

(i) 25×37\dfrac{2}{5} \times \dfrac{3}{7}

(ii) 35×89\dfrac{3}{5} \times \dfrac{8}{9}

(iii) 7×1237 \times 1\dfrac{2}{3}

Answer

(i) 25×37\dfrac{2}{5} \times \dfrac{3}{7}

2×35×7635\Rightarrow \dfrac{2 \times 3}{5 \times 7}\\[1em] \Rightarrow \dfrac{6}{35}

Hence, 25×37=635\dfrac{2}{5} \times \dfrac{3}{7} = \dfrac{6}{35}.

(ii) 35×89\dfrac{3}{5} \times \dfrac{8}{9}

3×85×939×8513×851×83×5815\Rightarrow \dfrac{3 \times 8}{5 \times 9}\\[1em] \Rightarrow \dfrac{3}{9} \times \dfrac{8}{5}\\[1em] \Rightarrow \dfrac{1}{3} \times \dfrac{8}{5}\\[1em] \Rightarrow \dfrac{1 \times 8}{3 \times 5}\\[1em] \Rightarrow \dfrac{8}{15}

Hence, 35×89=815\dfrac{3}{5} \times \dfrac{8}{9} = \dfrac{8}{15}.

(iii) 7×1237 \times 1\dfrac{2}{3}

7×537×533531123\Rightarrow 7 \times \dfrac{5}{3}\\[1em] \Rightarrow \dfrac{7 \times 5}{3}\\[1em] \Rightarrow \dfrac{35}{3}\\[1em] \Rightarrow 11\dfrac{2}{3}

Hence, 7×123=11237 \times 1\dfrac{2}{3} = 11\dfrac{2}{3}.

Question 2

Evaluate the following:

(i) 23×60\dfrac{2}{3} \times 60

(ii) 47×280\dfrac{4}{7} \times 280

(iii) 23\dfrac{2}{3} of 1491\dfrac{4}{9}

Answer

(i) 23×60\dfrac{2}{3} \times 60

2×6032×2040\Rightarrow \dfrac{2 \times 60}{3}\\[1em] \Rightarrow 2 \times 20\\[1em] \Rightarrow 40

Hence, 23×60=40\dfrac{2}{3} \times 60 = 40.

(ii) 47×280\dfrac{4}{7} \times 280

4×28074×40160\Rightarrow \dfrac{4 \times 280}{7}\\[1em] \Rightarrow 4 \times 40\\[1em] \Rightarrow 160

Hence, 47×280=160\dfrac{4}{7} \times 280 = 160.

(iii) 23\dfrac{2}{3} of 1491\dfrac{4}{9}

23×14923×1392×133×92627\Rightarrow \dfrac{2}{3} \times 1\dfrac{4}{9}\\[1em] \Rightarrow \dfrac{2}{3} \times \dfrac{13}{9}\\[1em] \Rightarrow \dfrac{2 \times 13}{3 \times 9}\\[1em] \Rightarrow \dfrac{26}{27}

Hence, 23\dfrac{2}{3} of 149=26271\dfrac{4}{9} = \dfrac{26}{27}.

Question 3

Find the reciprocal of each of the following fractions:

(i) 913\dfrac{9}{13}

(ii) 2382\dfrac{3}{8}

Answer

(i) 913\dfrac{9}{13}

The reciprocal of a fraction ab\dfrac{a}{b} is ba\dfrac{b}{a}.

So, the reciprocal of 913\dfrac{9}{13} is 139\dfrac{13}{9}.

Hence, the reciprocal of 913\dfrac{9}{13} is 139\dfrac{13}{9}.

(ii) 2382\dfrac{3}{8}

First, convert the mixed fraction into improper fraction.

238=2×8+38=198\Rightarrow 2\dfrac{3}{8} = \dfrac{2 \times 8 + 3}{8} = \dfrac{19}{8}

The reciprocal of 198\dfrac{19}{8} is 819\dfrac{8}{19}.

Hence, the reciprocal of 2382\dfrac{3}{8} is 819\dfrac{8}{19}.

Question 4

Evaluate the following:

(i) 821÷4\dfrac{8}{21} \div 4

(ii) 415÷25\dfrac{4}{15} \div \dfrac{2}{5}

(iii) 8÷568 \div \dfrac{5}{6}

(iv) 514÷785\dfrac{1}{4} \div \dfrac{7}{8}

(v) 513÷1195\dfrac{1}{3} \div 1\dfrac{1}{9}

Answer

(i) 821÷4\dfrac{8}{21} \div 4

821÷41821×1484×1212×121221\Rightarrow \dfrac{8}{21} \div \dfrac{4}{1}\\[1em] \Rightarrow \dfrac{8}{21} \times \dfrac{1}{4}\\[1em] \Rightarrow \dfrac{8}{4} \times \dfrac{1}{21}\\[1em] \Rightarrow 2 \times \dfrac{1}{21}\\[1em] \Rightarrow \dfrac{2}{21}

Hence, 821÷4=221\dfrac{8}{21} \div 4 = \dfrac{2}{21}.

(ii) 415÷25\dfrac{4}{15} \div \dfrac{2}{5}

415×5242×5152×1323\Rightarrow \dfrac{4}{15} \times \dfrac{5}{2}\\[1em] \Rightarrow \dfrac{4}{2} \times \dfrac{5}{15}\\[1em] \Rightarrow 2 \times \dfrac{1}{3}\\[1em] \Rightarrow \dfrac{2}{3}

Hence, 415÷25=23\dfrac{4}{15} \div \dfrac{2}{5} = \dfrac{2}{3}.

(iii) 8÷568 \div \dfrac{5}{6}

81÷5681×658×61×5485935\Rightarrow \dfrac{8}{1} \div \dfrac{5}{6}\\[1em] \Rightarrow \dfrac{8}{1} \times \dfrac{6}{5}\\[1em] \Rightarrow \dfrac{8 \times 6}{1 \times 5}\\[1em] \Rightarrow \dfrac{48}{5}\\[1em] \Rightarrow 9\dfrac{3}{5}

Hence, 8÷56=9358 \div \dfrac{5}{6} = 9\dfrac{3}{5}.

(iv) 514÷785\dfrac{1}{4} \div \dfrac{7}{8}

214÷78214×87217×843×26\Rightarrow \dfrac{21}{4} \div \dfrac{7}{8}\\[1em] \Rightarrow \dfrac{21}{4} \times \dfrac{8}{7}\\[1em] \Rightarrow \dfrac{21}{7} \times \dfrac{8}{4}\\[1em] \Rightarrow 3 \times 2\\[1em] \Rightarrow 6

Hence, 514÷78=65\dfrac{1}{4} \div \dfrac{7}{8} = 6.

(v) 513÷1195\dfrac{1}{3} \div 1\dfrac{1}{9}

163÷109163×9101610×9385×3245445\Rightarrow \dfrac{16}{3} \div \dfrac{10}{9}\\[1em] \Rightarrow \dfrac{16}{3} \times \dfrac{9}{10}\\[1em] \Rightarrow \dfrac{16}{10} \times \dfrac{9}{3}\\[1em] \Rightarrow \dfrac{8}{5} \times 3\\[1em] \Rightarrow \dfrac{24}{5}\\[1em] \Rightarrow 4\dfrac{4}{5}

Hence, 513÷119=4455\dfrac{1}{3} \div 1\dfrac{1}{9} = 4\dfrac{4}{5}.

Question 5

Find the following:

(i) 211\dfrac{2}{11} of ₹ 715

(ii) 49\dfrac{4}{9} of 405 kg

(iii) 37\dfrac{3}{7} of 4 hours 40 minutes

Answer

(i) 211\dfrac{2}{11} of ₹ 715

211×7152×715112×65130\Rightarrow \dfrac{2}{11} \times 715\\[1em] \Rightarrow \dfrac{2 \times 715}{11}\\[1em] \Rightarrow 2 \times 65\\[1em] \Rightarrow ₹130

Hence, 211\dfrac{2}{11} of ₹ 715 = ₹ 130.

(ii) 49\dfrac{4}{9} of 405 kg

49×4054×40594×45180 kg\Rightarrow \dfrac{4}{9} \times 405\\[1em] \Rightarrow \dfrac{4 \times 405}{9}\\[1em] \Rightarrow 4 \times 45\\[1em] \Rightarrow 180 \text{ kg}

Hence, 49\dfrac{4}{9} of 405 kg = 180 kg.

(iii) 37\dfrac{3}{7} of 4 hours 40 minutes

4 hours 40 minutes = (4 × 60 + 40) minutes = (240 + 40) minutes = 280 minutes.

37×280 minutes3×2807 minutes3×40 minutes120 minutes2 hours\Rightarrow \dfrac{3}{7} \times 280 \text{ minutes}\\[1em] \Rightarrow \dfrac{3 \times 280}{7} \text{ minutes}\\[1em] \Rightarrow 3 \times 40 \text{ minutes}\\[1em] \Rightarrow 120 \text{ minutes}\\[1em] \Rightarrow 2 \text{ hours}

Hence, 37\dfrac{3}{7} of 4 hours 40 minutes = 2 hours.

Question 6

Find the value of the following:

(i) 93

(ii) 84

(iii) (35)3\left(\dfrac{3}{5}\right)^3

(iv) 33 × 52

Answer

(i) 93

9×9×9729\Rightarrow 9 \times 9 \times 9\\[1em] \Rightarrow 729

Hence, 93 = 729.

(ii) 84

8×8×8×84096\Rightarrow 8 \times 8 \times 8 \times 8\\[1em] \Rightarrow 4096

Hence, 84 = 4096.

(iii) (35)3\left(\dfrac{3}{5}\right)^3

35×35×353×3×35×5×527125\Rightarrow \dfrac{3}{5} \times \dfrac{3}{5} \times \dfrac{3}{5}\\[1em] \Rightarrow \dfrac{3 \times 3 \times 3}{5 \times 5 \times 5}\\[1em] \Rightarrow \dfrac{27}{125}

Hence, (35)3=27125\left(\dfrac{3}{5}\right)^3 = \dfrac{27}{125}.

(iv) 33 × 52

(3×3×3)×(5×5)27×25675\Rightarrow (3 \times 3 \times 3) \times (5 \times 5)\\[1em] \Rightarrow 27 \times 25\\[1em] \Rightarrow 675

Hence, 33 × 52 = 675.

Exercise 6.7

Question 1

Nayamat bought 25\dfrac{2}{5} metre of ribbon and Amanat bought 34\dfrac{3}{4} metre of ribbon. What is the total length of the ribbon they bought?

Answer

Length of ribbon bought by Nayamat = 25\dfrac{2}{5} metre.

Length of ribbon bought by Amanat = 34\dfrac{3}{4} metre.

Total length of ribbon = 25+34\dfrac{2}{5} + \dfrac{3}{4}

LCM of 5 and 4 = 20.

2×45×4+3×54×5820+15208+152023201320 metre\Rightarrow \dfrac{2 \times 4}{5 \times 4} + \dfrac{3 \times 5}{4 \times 5}\\[1em] \Rightarrow \dfrac{8}{20} + \dfrac{15}{20}\\[1em] \Rightarrow \dfrac{8 + 15}{20}\\[1em] \Rightarrow \dfrac{23}{20}\\[1em] \Rightarrow 1\dfrac{3}{20} \text{ metre}

Hence, the total length of ribbon they bought = 13201\dfrac{3}{20} metre.

Question 2

A bamboo of length 2342\dfrac{3}{4} metre broke into two pieces. One piece was 78\dfrac{7}{8} metre long. How long is the other piece?

Answer

Total length of bamboo = 2342\dfrac{3}{4} metre.

Length of one piece = 78\dfrac{7}{8} metre.

Length of other piece = 234782\dfrac{3}{4} - \dfrac{7}{8}

LCM of 4 and 8 = 8.

1147811×24×278228782278158178 metre\Rightarrow \dfrac{11}{4} - \dfrac{7}{8}\\[1em] \Rightarrow \dfrac{11 \times 2}{4 \times 2} - \dfrac{7}{8}\\[1em] \Rightarrow \dfrac{22}{8} - \dfrac{7}{8}\\[1em] \Rightarrow \dfrac{22 - 7}{8}\\[1em] \Rightarrow \dfrac{15}{8}\\[1em] \Rightarrow 1\dfrac{7}{8} \text{ metre}

Hence, the length of the other piece = 1781\dfrac{7}{8} metre.

Question 3

Nidhi's house is 19101\dfrac{9}{10} km from her school. She walked some distance and then took a bus for 1121\dfrac{1}{2} km to reach the school. How far did she walk?

Answer

Total distance from house to school = 19101\dfrac{9}{10} km.

Distance travelled by bus = 1121\dfrac{1}{2} km.

Distance walked = 19101121\dfrac{9}{10} - 1\dfrac{1}{2}

LCM of 10 and 2 = 10.

19103219103×52×51910151019151041025 km\Rightarrow \dfrac{19}{10} - \dfrac{3}{2}\\[1em] \Rightarrow \dfrac{19}{10} - \dfrac{3 \times 5}{2 \times 5}\\[1em] \Rightarrow \dfrac{19}{10} - \dfrac{15}{10}\\[1em] \Rightarrow \dfrac{19 - 15}{10}\\[1em] \Rightarrow \dfrac{4}{10}\\[1em] \Rightarrow \dfrac{2}{5} \text{ km}

Hence, Nidhi walked 25\dfrac{2}{5} km.

Question 4

From a rope of length 201220\dfrac{1}{2} m, a piece of length 3583\dfrac{5}{8} m is cut off. Find the length of the remaining rope.

Answer

Total length of rope = 201220\dfrac{1}{2} m.

Length of piece cut off = 3583\dfrac{5}{8} m.

Length of remaining rope = 201235820\dfrac{1}{2} - 3\dfrac{5}{8}

LCM of 2 and 8 = 8.

41229841×42×4298164829816429813581678 m\Rightarrow \dfrac{41}{2} - \dfrac{29}{8}\\[1em] \Rightarrow \dfrac{41 \times 4}{2 \times 4} - \dfrac{29}{8}\\[1em] \Rightarrow \dfrac{164}{8} - \dfrac{29}{8}\\[1em] \Rightarrow \dfrac{164 - 29}{8}\\[1em] \Rightarrow \dfrac{135}{8}\\[1em] \Rightarrow 16\dfrac{7}{8} \text{ m}

Hence, the length of the remaining rope = 167816\dfrac{7}{8} m.

Question 5

The weights of three packets are 2342\dfrac{3}{4} kg, 3133\dfrac{1}{3} kg and 5255\dfrac{2}{5} kg. Find the total weight of all the three packets.

Answer

Weights of three packets = 2342\dfrac{3}{4} kg, 3133\dfrac{1}{3} kg and 5255\dfrac{2}{5} kg.

Total weight = 234+313+5252\dfrac{3}{4} + 3\dfrac{1}{3} + 5\dfrac{2}{5}

LCM of 4, 3 and 5 = 60.

114+103+27511×154×15+10×203×20+27×125×1216560+20060+32460165+200+3246068960112960 kg\Rightarrow \dfrac{11}{4} + \dfrac{10}{3} + \dfrac{27}{5}\\[1em] \Rightarrow \dfrac{11 \times 15}{4 \times 15} + \dfrac{10 \times 20}{3 \times 20} + \dfrac{27 \times 12}{5 \times 12}\\[1em] \Rightarrow \dfrac{165}{60} + \dfrac{200}{60} + \dfrac{324}{60}\\[1em] \Rightarrow \dfrac{165 + 200 + 324}{60}\\[1em] \Rightarrow \dfrac{689}{60}\\[1em] \Rightarrow 11\dfrac{29}{60} \text{ kg}

Hence, the total weight of the three packets = 11296011\dfrac{29}{60} kg.

Question 6

Shivani read 25 pages of a book containing 100 pages. Nandini read 25\dfrac{2}{5} of the same book. Who read less?

Answer

Total pages of book = 100.

Fraction of book read by Shivani = 25100=14\dfrac{25}{100} = \dfrac{1}{4}.

Fraction of book read by Nandini = 25\dfrac{2}{5}.

Now, compare 14\dfrac{1}{4} and 25\dfrac{2}{5}.

By cross multiplication,

1 × 5 = 5 and 4 × 2 = 8.

Since 5 < 8, therefore, 14<25\dfrac{1}{4} \lt \dfrac{2}{5}.

So, Shivani read less than Nandini.

Hence, Shivani read less.

Question 7

Ajay exercised for 36\dfrac{3}{6} of an hour, while Vijay exercised for 34\dfrac{3}{4} of an hour. Who exercised for a longer time and by what fraction of an hour?

Answer

Time for which Ajay exercised = 36\dfrac{3}{6} hour.

Time for which Vijay exercised = 34\dfrac{3}{4} hour.

Compare 36\dfrac{3}{6} and 34\dfrac{3}{4}.

These are unlike fractions with same numerator 3.

In fractions with same numerator, the fraction with smaller denominator is greater.

Since 4 < 6, therefore, 34>36\dfrac{3}{4} \gt \dfrac{3}{6}.

So, Vijay exercised for a longer time.

Difference = 3436\dfrac{3}{4} - \dfrac{3}{6}

LCM of 4 and 6 = 12.

3×34×33×26×2912612961231214 hour\Rightarrow \dfrac{3 \times 3}{4 \times 3} - \dfrac{3 \times 2}{6 \times 2}\\[1em] \Rightarrow \dfrac{9}{12} - \dfrac{6}{12}\\[1em] \Rightarrow \dfrac{9 - 6}{12}\\[1em] \Rightarrow \dfrac{3}{12}\\[1em] \Rightarrow \dfrac{1}{4} \text{ hour}

Hence, Vijay exercised for a longer time by 14\dfrac{1}{4} hour.

Objective Type Questions - Mental Maths

Question 1

Fill in the following blanks:

(i) A fraction is a number which represent a ..... of whole.

(ii) A proper fraction lies between 0 and .....

(iii) A mixed fraction can be converted into ..... fraction.

(iv) Fractions having different denominators are called .....

(v) 18135\dfrac{18}{135} and 72540\dfrac{72}{540} are proper, unlike and ...... fractions.

(vi) In two like fractions, the fraction having smaller numerator is .....

(vii) 144180\dfrac{144}{180} reduced to simplest form is .....

(viii) 7257\dfrac{2}{5} + .... = 12

(ix) 4256=6...\dfrac{42}{56} = \dfrac{6}{...}

Answer

(i) A fraction is a number which represent a part of whole.

(ii) A proper fraction lies between 0 and 1.

(iii) A mixed fraction can be converted into an improper fraction.

(iv) Fractions having different denominators are called unlike fractions.

(v) Check by cross multiplication: 18 × 540 = 9720 and 135 × 72 = 9720.

Since cross products are equal, the fractions are equivalent.

So, 18135\dfrac{18}{135} and 72540\dfrac{72}{540} are proper, unlike and equivalent fractions.

(vi) In two like fractions, the fraction having smaller numerator is smaller.

(vii) 144180\dfrac{144}{180}

By prime factorisation,

144180=2×2×2×2×3×32×2×3×3×5=2×25=45.\Rightarrow \dfrac{144}{180} = \dfrac{2 \times 2 \times 2 \times 2 \times 3 \times 3}{2 \times 2 \times 3 \times 3 \times 5}\\[1em] = \dfrac{2 \times 2}{5} \\[1em] = \dfrac{4}{5}.

So, 144180\dfrac{144}{180} reduced to simplest form is 45\dfrac{4}{5}.

(viii) 7257\dfrac{2}{5} + .... = 12

Required number = 12725=121375=605375=60375=235=43512 - 7\dfrac{2}{5} = \dfrac{12}{1} - \dfrac{37}{5} = \dfrac{60}{5} - \dfrac{37}{5} = \dfrac{60 - 37}{5} = \dfrac{23}{5} = 4\dfrac{3}{5}.

So, 7257\dfrac{2}{5} + 4354\dfrac{3}{5} = 12.

(ix) 4256=6...\dfrac{42}{56} = \dfrac{6}{...}

To get 6 from 42, we have to divide 42 by 7. So, divide 56 by 7.

4256=42÷756÷7=68\dfrac{42}{56} = \dfrac{42 \div 7}{56 \div 7} = \dfrac{6}{8}.

So, 4256=68\dfrac{42}{56} = \dfrac{6}{\textbf{8}}.

Question 2

State whether the following statements are true (T) or false (F):

(i) Two fractions with same numerator are called like fractions.

(ii) A fraction in which the numerator is greater than its denominator is called an improper fraction.

(iii) Every improper fraction can be converted into a mixed fraction.

(iv) Every fraction can be represented by a point on a number line.

(v) In two unlike fractions with same numerator, the fraction having greater denominator is greater.

(vi) 12,13\dfrac{1}{2}, \dfrac{1}{3} and 14\dfrac{1}{4} are like fractions.

Answer

(i) False.

Reason: Two fractions with same denominator are called like fractions, not same numerator.

(ii) True.

Reason: A fraction in which the numerator is greater than (or equal to) its denominator is called an improper fraction.

(iii) True.

Reason: Every improper fraction can be converted into a mixed fraction by dividing the numerator by the denominator.

(iv) True.

Reason: Every fraction has a unique position on the number line.

(v) False.

Reason: In two unlike fractions with same numerator, the fraction having smaller denominator is greater (not greater denominator).

(vi) False.

Reason: 12,13\dfrac{1}{2}, \dfrac{1}{3} and 14\dfrac{1}{4} have different denominators (2, 3, 4), so they are unlike fractions, not like fractions.

Multiple Choice Questions

Question 3

In the adjoining figure, the shaded part is represented by the fraction:

In the adjoining figure, the shaded part is represented by the fraction: Fractions, ML Aggarwal Understanding Mathematics Solutions ICSE Class 6.
  1. 38\dfrac{3}{8}

  2. 37\dfrac{3}{7}

  3. 48\dfrac{4}{8}

  4. 36\dfrac{3}{6}

Answer

Total parts = 7

Shaded parts = 3

Fraction = No. of shaded partsTotal parts=37\dfrac{\text{No. of shaded parts}}{\text{Total parts}} = \dfrac{3}{7}.

Hence, option 2 is the correct option.

Question 4

In the adjoining figure, the shaded region is represented by the fraction:

In the adjoining figure, the shaded region is represented by the fraction: Fractions, ML Aggarwal Understanding Mathematics Solutions ICSE Class 6.
  1. 412\dfrac{4}{12}

  2. 512\dfrac{5}{12}

  3. 524\dfrac{5}{24}

  4. 424\dfrac{4}{24}

Answer

Total parts = 12

Shaded parts = 1+12+12=521 + \dfrac{1}{2} + \dfrac{1}{2} = \dfrac{5}{2}

Fraction = Shaded partsTotal parts=5212=52×12=524\dfrac{\text{Shaded parts}}{\text{Total parts}} = \dfrac{\dfrac{5}{2}}{12} = \dfrac{5}{2 \times 12} = \dfrac{5}{24}.

Hence, option 3 is the correct option.

Question 5

The two consecutive integers between which the fraction 57\dfrac{5}{7} lies are

  1. 5 and 7

  2. 5 and 6

  3. 6 and 7

  4. 0 and 1

Answer

The fraction 57\dfrac{5}{7} is a proper fraction (numerator < denominator).

All proper fractions lie between 0 and 1.

Hence, option 4 is the correct option.

Question 6

Which of the following pairs of fractions are not equivalent?

  1. 34,1520\dfrac{3}{4}, \dfrac{15}{20}

  2. 1421,46\dfrac{14}{21}, \dfrac{4}{6}

  3. 810,1215\dfrac{8}{10}, \dfrac{12}{15}

  4. 614,1025\dfrac{6}{14}, \dfrac{10}{25}

Answer

Check each option using cross multiplication:

  1. 3 × 20 = 60 and 4 × 15 = 60. Equal, so equivalent.

  2. 14 × 6 = 84 and 21 × 4 = 84. Equal, so equivalent.

  3. 8 × 15 = 120 and 10 × 12 = 120. Equal, so equivalent.

  4. 6 × 25 = 150 and 14 × 10 = 140. Not equal, so not equivalent.

Hence, option 4 is the correct option.

Question 7

The fraction equivalent to 4581\dfrac{45}{81} is

  1. 90243\dfrac{90}{243}

  2. 159\dfrac{15}{9}

  3. 527\dfrac{5}{27}

  4. 59\dfrac{5}{9}

Answer

By prime factorisation,

4581=3×3×53×3×3×3=53×3=59.\Rightarrow \dfrac{45}{81} = \dfrac{3 \times 3 \times 5}{3 \times 3 \times 3 \times 3}\\[1em] = \dfrac{5}{3 \times 3}\\[1em] = \dfrac{5}{9}.

Hence, option 4 is the correct option.

Question 8

The fraction which is not equal to 45\dfrac{4}{5} is

  1. 4050\dfrac{40}{50}

  2. 915\dfrac{9}{15}

  3. 1215\dfrac{12}{15}

  4. 3240\dfrac{32}{40}

Answer

Check each option using cross multiplication with 45\dfrac{4}{5}:

  1. 4 × 50 = 200 and 5 × 40 = 200. Equal, so equivalent.

  2. 4 × 15 = 60 and 5 × 9 = 45. Not equal, so not equivalent.

  3. 4 × 15 = 60 and 5 × 12 = 60. Equal, so equivalent.

  4. 4 × 40 = 160 and 5 × 32 = 160. Equal, so equivalent.

Hence, option 2 is the correct option.

Question 9

Which of the following fractions is not in the simplest form?

  1. 2728\dfrac{27}{28}

  2. 1333\dfrac{13}{33}

  3. 3987\dfrac{39}{87}

  4. 149\dfrac{14}{9}

Answer

A fraction is in simplest form if HCF of numerator and denominator is 1.

  1. HCF of 27 and 28 = 1. So, simplest form.

  2. HCF of 13 and 33 = 1. So, simplest form.

  3. HCF of 39 and 87 = 3. So, not in simplest form.

3987=39÷387÷3=1329\dfrac{39}{87} = \dfrac{39 \div 3}{87 \div 3} = \dfrac{13}{29}.

  1. HCF of 14 and 9 = 1. So, simplest form.

Hence, option 3 is the correct option.

Question 10

A pair of like fractions is

  1. 34,35\dfrac{3}{4}, \dfrac{3}{5}

  2. 37,167\dfrac{3}{7}, \dfrac{16}{7}

  3. 56,65\dfrac{5}{6}, \dfrac{6}{5}

  4. 23,25\dfrac{2}{3}, \dfrac{2}{5}

Answer

Like fractions have the same denominator.

In option 2, 37\dfrac{3}{7} and 167\dfrac{16}{7} have the same denominator 7.

Hence, option 2 is the correct option.

Question 11

Which of the following fractions is the greatest?

  1. 56\dfrac{5}{6}

  2. 57\dfrac{5}{7}

  3. 58\dfrac{5}{8}

  4. 59\dfrac{5}{9}

Answer

These are unlike fractions with same numerator 5.

In fractions with same numerator, the fraction with smaller denominator is greater.

The smallest denominator is 6.

So, 56\dfrac{5}{6} is the greatest.

Hence, option 1 is the correct option.

Question 12

Which of the following fractions is the smallest?

  1. 117\dfrac{11}{7}

  2. 119\dfrac{11}{9}

  3. 1110\dfrac{11}{10}

  4. 116\dfrac{11}{6}

Answer

These are unlike fractions with same numerator 11.

In fractions with same numerator, the fraction with greater denominator is smaller.

The greatest denominator is 10.

So, 1110\dfrac{11}{10} is the smallest.

Hence, option 3 is the correct option.

Question 13

Which of the following is a false statement?

  1. 17<314\dfrac{1}{7} \lt \dfrac{3}{14}

  2. 58=1524\dfrac{5}{8} = \dfrac{15}{24}

  3. 34=616\dfrac{3}{4} = \dfrac{6}{16}

  4. 512>26\dfrac{5}{12} \gt \dfrac{2}{6}

Answer

Check each option:

  1. Cross multiplication: 1 × 14 = 14 and 7 × 3 = 21. Since 14 < 21, 17<314\dfrac{1}{7} \lt \dfrac{3}{14}. True.

  2. Cross multiplication: 5 × 24 = 120 and 8 × 15 = 120. Equal, so 58=1524\dfrac{5}{8} = \dfrac{15}{24}. True.

  3. Cross multiplication: 3 × 16 = 48 and 4 × 6 = 24. Not equal, so 34616\dfrac{3}{4} \neq \dfrac{6}{16}. False.

  4. Cross multiplication: 5 × 6 = 30 and 12 × 2 = 24. Since 30 > 24, 512>26\dfrac{5}{12} \gt \dfrac{2}{6}. True.

Hence, option 3 is the correct option.

Question 14

17+414\dfrac{1}{7} + \dfrac{4}{14} is equal to

  1. 514\dfrac{5}{14}

  2. 57\dfrac{5}{7}

  3. 314\dfrac{3}{14}

  4. 37\dfrac{3}{7}

Answer

LCM of 7 and 14 = 14.

1×27×2+414214+4142+41461437\Rightarrow \dfrac{1 \times 2}{7 \times 2} + \dfrac{4}{14}\\[1em] \Rightarrow \dfrac{2}{14} + \dfrac{4}{14}\\[1em] \Rightarrow \dfrac{2 + 4}{14}\\[1em] \Rightarrow \dfrac{6}{14}\\[1em] \Rightarrow \dfrac{3}{7}

Hence, option 4 is the correct option.

Question 15

79518\dfrac{7}{9} - \dfrac{5}{18} is equal to

  1. 218\dfrac{2}{18}

  2. 29\dfrac{2}{9}

  3. 12\dfrac{1}{2}

  4. 1118\dfrac{11}{18}

Answer

LCM of 9 and 18 = 18.

7×29×251814185181451891812\Rightarrow \dfrac{7 \times 2}{9 \times 2} - \dfrac{5}{18}\\[1em] \Rightarrow \dfrac{14}{18} - \dfrac{5}{18}\\[1em] \Rightarrow \dfrac{14 - 5}{18}\\[1em] \Rightarrow \dfrac{9}{18}\\[1em] \Rightarrow \dfrac{1}{2}

Hence, option 3 is the correct option.

Question 16

Anshul eats 47\dfrac{4}{7} of a pizza. The fraction of the pizza left is

  1. 37\dfrac{3}{7}

  2. 27\dfrac{2}{7}

  3. 57\dfrac{5}{7}

  4. 17\dfrac{1}{7}

Answer

Fraction of pizza eaten = 47\dfrac{4}{7}.

Fraction of pizza left = 1471 - \dfrac{4}{7}

774774737\Rightarrow \dfrac{7}{7} - \dfrac{4}{7}\\[1em] \Rightarrow \dfrac{7 - 4}{7}\\[1em] \Rightarrow \dfrac{3}{7}

Hence, option 1 is the correct option.

Question 17

The fraction whose numerator is the smallest odd prime number and denominator is the smallest composite number is

  1. 34\dfrac{3}{4}

  2. 24\dfrac{2}{4}

  3. 43\dfrac{4}{3}

  4. 42\dfrac{4}{2}

Answer

Smallest odd prime number = 3.

Smallest composite number = 4.

So, the required fraction = 34\dfrac{3}{4}.

Hence, option 1 is the correct option.

Statement I-II Type Questions

Question 18

Statement I: 3473\dfrac{4}{7} is a mixed fraction.

Statement II: A natural number added to a proper fraction forms an improper fraction.

  1. Statement I is true but statement II is false.

  2. Statement I is false but statement II is true.

  3. Both Statement I and statement II are true.

  4. Both Statement I and statement II are false.

Answer

According to Statement I, 3473\dfrac{4}{7} consists of a natural number 3 and a proper fraction 47\dfrac{4}{7}.

So, 3473\dfrac{4}{7} is a mixed fraction.

∴ Statement I is true.

According to Statement II, a natural number added to a proper fraction forms a mixed fraction (which can also be written as an improper fraction).

For example, 3+47=347=2573 + \dfrac{4}{7} = 3\dfrac{4}{7} = \dfrac{25}{7}, which is an improper fraction.

∴ Statement II is true.

Both Statement I and Statement II are true.

Hence, option 3 is the correct option.

Question 19

Statement I: An orchard has a total area of 1000 m2. Given that 200 m2 of the orchard has been used for mango trees, 500 m2 has been used for apple trees and the remaining area is unused. The fraction of the orchard that is unused is 310\dfrac{3}{10}.

Statement II: All natural numbers can be written as improper fractions.

  1. Statement I is true but statement II is false.

  2. Statement I is false but statement II is true.

  3. Both Statement I and statement II are true.

  4. Both Statement I and statement II are false.

Answer

According to Statement I,

Total area = 1000 m2

Area used = 200 + 500 = 700 m2

Unused area = 1000 - 700 = 300 m2

Fraction of unused area = 3001000=310\dfrac{300}{1000} = \dfrac{3}{10}.

∴ Statement I is true.

According to Statement II, every natural number can be written with denominator 1.

For example, 5=515 = \dfrac{5}{1}, 21=21121 = \dfrac{21}{1}, etc., which are improper fractions (numerator ≥ denominator).

∴ Statement II is true.

Both Statement I and Statement II are true.

Hence, option 3 is the correct option.

Question 20

Statement I: Karishma earns a monthly salary of ₹50,000. She donates ₹5000 to charity and spends ₹6000 for groceries. The reciprocal of the fraction corresponding to her savings is =5039= \dfrac{50}{39}.

Statement II: As 5039×3950=1\dfrac{50}{39} \times \dfrac{39}{50} = 1, therefore, 5039\dfrac{50}{39} and 3950\dfrac{39}{50} are reciprocals of each other.

  1. Statement I is true but statement II is false.

  2. Statement I is false but statement II is true.

  3. Both Statement I and statement II are true.

  4. Both Statement I and statement II are false.

Answer

According to Statement I,

Total salary = ₹50,000.

Total spent = 5000 + 6000 = ₹11,000.

Savings = 50,000 - 11,000 = ₹39,000.

Fraction of savings = 39,00050,000=3950\dfrac{39,000}{50,000} = \dfrac{39}{50}.

Reciprocal of 3950\dfrac{39}{50} = 5039\dfrac{50}{39}.

∴ Statement I is true.

According to Statement II, two numbers are reciprocals of each other if their product is 1.

5039×3950=50×3939×50=1\dfrac{50}{39} \times \dfrac{39}{50} = \dfrac{50 \times 39}{39 \times 50} = 1.

So, 5039\dfrac{50}{39} and 3950\dfrac{39}{50} are reciprocals of each other.

∴ Statement II is true.

Both Statement I and Statement II are true.

Hence, option 3 is the correct option.

Check Your Progress

Question 1

State whether the following statements are true (T) or false (F):

(i) The fraction 23\dfrac{2}{3} lies between 2 and 3

(ii) To find an equivalent fraction to a given fraction, we may add or subtract the same (non-zero) number to its numerator and denominator.

Answer

(i) False.

Reason: 23\dfrac{2}{3} is a proper fraction (numerator < denominator), so it lies between 0 and 1, not between 2 and 3.

(ii) False.

Reason: To find an equivalent fraction, we must multiply or divide the numerator and denominator by the same non-zero number, not add or subtract.

Question 2

How many natural numbers are there between 102 and 112? What fraction of them are prime numbers?

Answer

Natural numbers between 102 and 112 are:

103, 104, 105, 106, 107, 108, 109, 110, 111 and their number = 9.

Out of these, the prime numbers are:

103, 107, 109 and their number = 3.

Fraction of prime numbers = Number of primesTotal numbers=39=13\dfrac{\text{Number of primes}}{\text{Total numbers}} = \dfrac{3}{9} = \dfrac{1}{3}.

Hence, total natural numbers = 9 and fraction of prime numbers = 13\dfrac{1}{3}.

Question 3

Find the numbers p and q in: 58=20p=q104\dfrac{5}{8} = \dfrac{20}{p} = \dfrac{q}{104}

Answer

To find p:

58=20p\dfrac{5}{8} = \dfrac{20}{p}

To get 20 from 5, we have to multiply 5 by 4.

So, multiply both numerator and denominator by 4.

58=5×48×4=2032.\Rightarrow \dfrac{5}{8} = \dfrac{5 \times 4}{8 \times 4} = \dfrac{20}{32}.

So, p = 32.

To find q:

58=q104\dfrac{5}{8} = \dfrac{q}{104}

To get 104 from 8, we have to multiply 8 by 13.

So, multiply both numerator and denominator by 13.

58=5×138×13=65104.\Rightarrow \dfrac{5}{8} = \dfrac{5 \times 13}{8 \times 13} = \dfrac{65}{104}.

So, q = 65.

Hence, p = 32 and q = 65.

Question 4

Match the equivalent fractions from each row:

(i) 250400\dfrac{250}{400}

(ii) 180200\dfrac{180}{200}

(iii) 660990\dfrac{660}{990}

(iv) 180360\dfrac{180}{360}

(v) 220550\dfrac{220}{550}

(a) 23\dfrac{2}{3}

(b) 25\dfrac{2}{5}

(c) 12\dfrac{1}{2}

(d) 58\dfrac{5}{8}

(e) 910\dfrac{9}{10}

Answer

Reduce each fraction to its simplest form:

(i) 250400=250÷50400÷50=58\dfrac{250}{400} = \dfrac{250 \div 50}{400 \div 50} = \dfrac{5}{8}. Matches with (d).

(ii) 180200=180÷20200÷20=910\dfrac{180}{200} = \dfrac{180 \div 20}{200 \div 20} = \dfrac{9}{10}. Matches with (e).

(iii) 660990=660÷330990÷330=23\dfrac{660}{990} = \dfrac{660 \div 330}{990 \div 330} = \dfrac{2}{3}. Matches with (a).

(iv) 180360=180÷180360÷180=12\dfrac{180}{360} = \dfrac{180 \div 180}{360 \div 180} = \dfrac{1}{2}. Matches with (c).

(v) 220550=220÷110550÷110=25\dfrac{220}{550} = \dfrac{220 \div 110}{550 \div 110} = \dfrac{2}{5}. Matches with (b).

Hence, the matches are:

(i) ↔ (d), (ii) ↔ (e), (iii) ↔ (a), (iv) ↔ (c), (v) ↔ (b).

Question 5

Replace '653\boxed{\phantom{653}}' by an appropriate symbol '< or >' between the given fractions:

(i) 566531315\dfrac{5}{6} \boxed{\phantom{653}} \dfrac{13}{15}

(ii) 45\dfrac{4}{5} 653\boxed{\phantom{653}} 79\dfrac{7}{9}

(iii) 1112\dfrac{11}{12} 653\boxed{\phantom{653}} 1314\dfrac{13}{14}

Answer

(i) 56\dfrac{5}{6} and 1315\dfrac{13}{15}

By cross multiplication,

5 × 15 = 75 and 6 × 13 = 78.

Since 75 < 78, therefore, 56<1315\dfrac{5}{6} \lt \dfrac{13}{15}.

Hence, 56<1315\dfrac{5}{6} \lt \dfrac{13}{15}.

(ii) 45\dfrac{4}{5} and 79\dfrac{7}{9}

By cross multiplication,

4 × 9 = 36 and 5 × 7 = 35.

Since 36 > 35, therefore, 45>79\dfrac{4}{5} \gt \dfrac{7}{9}.

Hence, 45>79\dfrac{4}{5} \gt \dfrac{7}{9}.

(iii) 1112\dfrac{11}{12} and 1314\dfrac{13}{14}

By cross multiplication,

11 × 14 = 154 and 12 × 13 = 156.

Since 154 < 156, therefore, 1112<1314\dfrac{11}{12} \lt \dfrac{13}{14}.

Hence, 1112<1314\dfrac{11}{12} \lt \dfrac{13}{14}.

Question 6

Arrange the following fractions in descending order: 730,1315,910,35\dfrac{7}{30}, \dfrac{13}{15}, \dfrac{9}{10}, \dfrac{3}{5}

Answer

LCM of 30, 15, 10 and 5 = 30.

Write the given fractions as equivalent like fractions.

730=7301315=13×215×2=2630910=9×310×3=273035=3×65×6=1830\Rightarrow \dfrac{7}{30} = \dfrac{7}{30} \\[1em] \Rightarrow \dfrac{13}{15} = \dfrac{13 \times 2}{15 \times 2} = \dfrac{26}{30} \\[1em] \Rightarrow \dfrac{9}{10} = \dfrac{9 \times 3}{10 \times 3} = \dfrac{27}{30} \\[1em] \Rightarrow \dfrac{3}{5} = \dfrac{3 \times 6}{5 \times 6} = \dfrac{18}{30}

As 27 > 26 > 18 > 7,

2730>2630>1830>730910>1315>35>730\dfrac{27}{30} \gt \dfrac{26}{30} \gt \dfrac{18}{30} \gt \dfrac{7}{30} \Rightarrow \dfrac{9}{10} \gt \dfrac{13}{15} \gt \dfrac{3}{5} \gt \dfrac{7}{30}.

Hence, the given fractions in descending order are 910,1315,35,730\dfrac{9}{10}, \dfrac{13}{15}, \dfrac{3}{5}, \dfrac{7}{30}.

Question 7

Simplify: 212314+5562\dfrac{1}{2} - 3\dfrac{1}{4} + 5\dfrac{5}{6}

Answer

LCM of 2, 4 and 6 = 12.

52134+3565×62×613×34×3+35×26×230123912+70123039+701261125112\Rightarrow \dfrac{5}{2} - \dfrac{13}{4} + \dfrac{35}{6}\\[1em] \Rightarrow \dfrac{5 \times 6}{2 \times 6} - \dfrac{13 \times 3}{4 \times 3} + \dfrac{35 \times 2}{6 \times 2}\\[1em] \Rightarrow \dfrac{30}{12} - \dfrac{39}{12} + \dfrac{70}{12}\\[1em] \Rightarrow \dfrac{30 - 39 + 70}{12}\\[1em] \Rightarrow \dfrac{61}{12}\\[1em] \Rightarrow 5\dfrac{1}{12}

Hence, 212314+556=51122\dfrac{1}{2} - 3\dfrac{1}{4} + 5\dfrac{5}{6} = 5\dfrac{1}{12}.

Question 8

Evaluate the following:

(i) 35×180\dfrac{3}{5} \times 180

(ii) 37\dfrac{3}{7} of 5565\dfrac{5}{6}

(iii) 518÷23\dfrac{5}{18} \div \dfrac{2}{3}

Answer

(i) 35×180\dfrac{3}{5} \times 180

3×18053×36108\Rightarrow \dfrac{3 \times 180}{5}\\[1em] \Rightarrow 3 \times 36\\[1em] \Rightarrow 108

Hence, 35×180=108\dfrac{3}{5} \times 180 = 108.

(ii) 37\dfrac{3}{7} of 5565\dfrac{5}{6}

37×35636×35712×552212\Rightarrow \dfrac{3}{7} \times \dfrac{35}{6}\\[1em] \Rightarrow \dfrac{3}{6} \times \dfrac{35}{7}\\[1em] \Rightarrow \dfrac{1}{2} \times 5\\[1em] \Rightarrow \dfrac{5}{2}\\[1em] \Rightarrow 2\dfrac{1}{2}

Hence, 37\dfrac{3}{7} of 556=2125\dfrac{5}{6} = 2\dfrac{1}{2}.

(iii) 518÷23\dfrac{5}{18} \div \dfrac{2}{3}

518×3252×31852×16512\Rightarrow \dfrac{5}{18} \times \dfrac{3}{2}\\[1em] \Rightarrow \dfrac{5}{2} \times \dfrac{3}{18}\\[1em] \Rightarrow \dfrac{5}{2} \times \dfrac{1}{6}\\[1em] \Rightarrow \dfrac{5}{12}

Hence, 518÷23=512\dfrac{5}{18} \div \dfrac{2}{3} = \dfrac{5}{12}.

Question 9

Asha and Samuel have bookshelves of the same size partly filled with books. Asha's shelf is 56\dfrac{5}{6} full and Samuel's shelf is 35\dfrac{3}{5} full. Whose bookshelf is more full and by what fraction?

Answer

Asha's shelf = 56\dfrac{5}{6} full.

Samuel's shelf = 35\dfrac{3}{5} full.

Compare 56\dfrac{5}{6} and 35\dfrac{3}{5} by cross multiplication:

5 × 5 = 25 and 6 × 3 = 18.

Since 25 > 18, therefore, 56>35\dfrac{5}{6} \gt \dfrac{3}{5}.

So, Asha's bookshelf is more full.

Difference = 5635\dfrac{5}{6} - \dfrac{3}{5}

LCM of 6 and 5 = 30.

5×56×53×65×625301830251830730\Rightarrow \dfrac{5 \times 5}{6 \times 5} - \dfrac{3 \times 6}{5 \times 6}\\[1em] \Rightarrow \dfrac{25}{30} - \dfrac{18}{30}\\[1em] \Rightarrow \dfrac{25 - 18}{30}\\[1em] \Rightarrow \dfrac{7}{30}

Hence, Asha's bookshelf is more full by 730\dfrac{7}{30}.

Question 10

A farmer uses four out of five equal strips of his land for wheat crop and 17\dfrac{1}{7} of his land for cereal crop. What fraction of his land is available for other crops?

Answer

Fraction of land used for wheat crop = 45\dfrac{4}{5}.

Fraction of land used for cereal crop = 17\dfrac{1}{7}.

Total fraction used = 45+17\dfrac{4}{5} + \dfrac{1}{7}

LCM of 5 and 7 = 35.

4×75×7+1×57×52835+53528+5353335\Rightarrow \dfrac{4 \times 7}{5 \times 7} + \dfrac{1 \times 5}{7 \times 5}\\[1em] \Rightarrow \dfrac{28}{35} + \dfrac{5}{35}\\[1em] \Rightarrow \dfrac{28 + 5}{35}\\[1em] \Rightarrow \dfrac{33}{35}

Fraction of land available for other crops = 133351 - \dfrac{33}{35}

35353335353335235\Rightarrow \dfrac{35}{35} - \dfrac{33}{35}\\[1em] \Rightarrow \dfrac{35 - 33}{35}\\[1em] \Rightarrow \dfrac{2}{35}

Hence, the fraction of land available for other crops = 235\dfrac{2}{35}.

Question 11

A rectangle is divided into a certain number of equal parts. If 16 of the parts so formed represents the fraction 25\dfrac{2}{5}, find the number of parts in which the rectangle has been divided.

Answer

Let the total number of parts be x.

Given, 16 parts represent the fraction 25\dfrac{2}{5}.

16x=2516×5=2×x80=2xx=802x=40\Rightarrow \dfrac{16}{x} = \dfrac{2}{5}\\[1em] \Rightarrow 16 \times 5 = 2 \times x\\[1em] \Rightarrow 80 = 2x\\[1em] \Rightarrow x = \dfrac{80}{2}\\[1em] \Rightarrow x = 40

Hence, the rectangle is divided into 40 equal parts.

Question 12

Find the value of the following:

(i) 55

(ii) (34)4\left(\dfrac{3}{4}\right)^4

Answer

(i) 55

5×5×5×5×53125\Rightarrow 5 \times 5 \times 5 \times 5 \times 5\\[1em] \Rightarrow 3125

Hence, 55 = 3125.

(ii) (34)4\left(\dfrac{3}{4}\right)^4

34×34×34×343×3×3×34×4×4×481256\Rightarrow \dfrac{3}{4} \times \dfrac{3}{4} \times \dfrac{3}{4} \times \dfrac{3}{4}\\[1em] \Rightarrow \dfrac{3 \times 3 \times 3 \times 3}{4 \times 4 \times 4 \times 4}\\[1em] \Rightarrow \dfrac{81}{256}

Hence, (34)4=81256\left(\dfrac{3}{4}\right)^4 = \dfrac{81}{256}.

Question 13

Write all proper fractions whose sum of numerator and denominator is 12.

Answer

A proper fraction has numerator less than denominator.

We need pairs of (numerator, denominator) such that numerator + denominator = 12 and numerator < denominator.

Numerator + denominator = 12 with numerator < denominator means numerator < 6.

The possible fractions are:

If numerator = 1, denominator = 11 → 111\dfrac{1}{11}.

If numerator = 2, denominator = 10 → 210\dfrac{2}{10}.

If numerator = 3, denominator = 9 → 39\dfrac{3}{9}.

If numerator = 4, denominator = 8 → 48\dfrac{4}{8}.

If numerator = 5, denominator = 7 → 57\dfrac{5}{7}.

Hence, the proper fractions are: 111,210,39,48\dfrac{1}{11}, \dfrac{2}{10}, \dfrac{3}{9}, \dfrac{4}{8} and 57\dfrac{5}{7}.

Question 14

Find the value of xx if 4x12+113=5344\dfrac{x}{12} + 1\dfrac{1}{3} = 5\dfrac{3}{4}

Answer

4x12+113=5344x12=5341134x12=23443\Rightarrow 4\dfrac{x}{12} + 1\dfrac{1}{3} = 5\dfrac{3}{4}\\[1em] \Rightarrow 4\dfrac{x}{12} = 5\dfrac{3}{4} - 1\dfrac{1}{3}\\[1em] \Rightarrow 4\dfrac{x}{12} = \dfrac{23}{4} - \dfrac{4}{3}

LCM of 4 and 3 = 12.

4x12=23×34×34×43×44x12=691216124x12=6916124x12=53124x12=4512\Rightarrow 4\dfrac{x}{12} = \dfrac{23 \times 3}{4 \times 3} - \dfrac{4 \times 4}{3 \times 4}\\[1em] \Rightarrow 4\dfrac{x}{12} = \dfrac{69}{12} - \dfrac{16}{12}\\[1em] \Rightarrow 4\dfrac{x}{12} = \dfrac{69 - 16}{12}\\[1em] \Rightarrow 4\dfrac{x}{12} = \dfrac{53}{12}\\[1em] \Rightarrow 4\dfrac{x}{12} = 4\dfrac{5}{12}

Comparing both sides, x = 5.

Hence, x = 5.

Question 15

The adjoining figure represents the preferences of the students during breakfast in a hostel mess. If the total number of students in the mess is 540, then with reference to the given figure, answer the following questions:

Here are two different factor trees of the number 90. Write the missing numbers: Fractions, ML Aggarwal Understanding Mathematics Solutions ICSE Class 6.

(i) What is the number of students who prefer coffee?

(ii) Whose number is greater, milk drinkers or orange juice drinkers and by what number?

(iii) What is the total number of students who drink mango shake or coffee? Is it equal to milk drinker?

(iv) Is the sum of all fractions in the given figure equal to 1?

Answer

Total number of students = 540.

From the figure, the fractions are:

Orange juice = 14\dfrac{1}{4}, Milk = 13\dfrac{1}{3}, Tea = 112\dfrac{1}{12}, Coffee = 16\dfrac{1}{6}, Mango shake = 16\dfrac{1}{6}.

(i) Number of students who prefer coffee = 16×540\dfrac{1}{6} \times 540

540690\Rightarrow \dfrac{540}{6}\\[1em] \Rightarrow 90

Hence, the number of students who prefer coffee = 90.

(ii) Number of milk drinkers = 13×540=5403=180\dfrac{1}{3} \times 540 = \dfrac{540}{3} = 180.

Number of orange juice drinkers = 14×540=5404=135\dfrac{1}{4} \times 540 = \dfrac{540}{4} = 135.

Since 180 > 135, milk drinkers are more than orange juice drinkers.

Difference = 180 - 135 = 45.

Hence, milk drinkers are greater than orange juice drinkers by 45.

(iii) Number of mango shake drinkers = 16×540=90\dfrac{1}{6} \times 540 = 90.

Number of coffee drinkers = 90.

Total = 90 + 90 = 180.

Number of milk drinkers = 180.

Yes, total of mango shake and coffee drinkers (180) is equal to milk drinkers (180).

Hence, the total number of students who drink mango shake or coffee = 180, which is equal to the number of milk drinkers.

(iv) Sum of all fractions = 14+13+112+16+16\dfrac{1}{4} + \dfrac{1}{3} + \dfrac{1}{12} + \dfrac{1}{6} + \dfrac{1}{6}

LCM of 4, 3, 12, 6 = 12.

1×34×3+1×43×4+112+1×26×2+1×26×2312+412+112+212+2123+4+1+2+21212121\Rightarrow \dfrac{1 \times 3}{4 \times 3} + \dfrac{1 \times 4}{3 \times 4} + \dfrac{1}{12} + \dfrac{1 \times 2}{6 \times 2} + \dfrac{1 \times 2}{6 \times 2}\\[1em] \Rightarrow \dfrac{3}{12} + \dfrac{4}{12} + \dfrac{1}{12} + \dfrac{2}{12} + \dfrac{2}{12}\\[1em] \Rightarrow \dfrac{3 + 4 + 1 + 2 + 2}{12}\\[1em] \Rightarrow \dfrac{12}{12}\\[1em] \Rightarrow 1

Hence, yes, the sum of all fractions in the given figure is equal to 1.

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