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Chapter 2

Operations on Whole Numbers — Exercise 2(B)

Class - 6 RS Aggarwal Mathematics Solutions



Exercise 2(B)

Question 1(i)

Study the following pattern. In each case write the next three steps :

111 ÷ 3 = 37

222 ÷ 6 = 37

333 ÷ 9 = 37

444 ÷ 12 = 37

Answer

111 ÷ 3 = 37

222 ÷ 6 = 37

333 ÷ 9 = 37

444 ÷ 12 = 37

The numerator increases by 111 and the divisor increases by 3.

Thus, next three steps are :

555 ÷ 15 = 37

666 ÷ 18 = 37

777 ÷ 21 = 37

Question 1(ii)

Study the following pattern. In each case write the next three steps :

999999 x 1 = 0999999

999999 x 2 = 1999998

999999 x 3 = 2999997

999999 x 4 = 3999996

Answer

999999 x 1 = 0999999

999999 x 2 = 1999998

999999 x 3 = 2999997

999999 x 4 = 3999996

The multiplier increases by 1 and the pattern continues accordingly.

Thus, next three steps are :

999999 x 5 = 4999995

999999 x 6 = 5999994

999999 x 7 = 6999993

Question 1(iii)

Study the following pattern. In each case write the next three steps :

12345679 x 9 = 111111111

12345679 x 18 = 222222222

12345679 x 27 = 333333333

12345679 x 36 = 444444444

Answer

12345679 x 9 = 111111111

12345679 x 18 = 222222222

12345679 x 27 = 333333333

12345679 x 36 = 444444444

The multiplier increases by 9 each time and the product forms repeated digits.

Thus, next three steps are :

12345679 x 45 = 555555555

12345679 x 54 = 666666666

12345679 x 63 = 777777777

Question 2

Observe the following pattern and answer the questions that follow :

1 + 2 + 3 + 4 + 5 = 15

2 + 3 + 4 + 5 + 6 = 20

3 + 4 + 5 + 6 + 7 = 25

(i) By which number should we multiply the middle number to get the sum?

(ii) Write the row of the pattern which gives the sum as 75.

(iii) Can there be any row of the pattern which gives the sum as 92?

Answer

(i) Observing the pattern:

1 + 2 + 3 + 4 + 5 = 15. The middle number is 3 and 3 x 5 = 15.

2 + 3 + 4 + 5 + 6 = 20. The middle number is 4 and 4 x 5 = 20.

3 + 4 + 5 + 6 + 7 = 25. The middle number is 5 and 5 x 5 = 25.

The pattern shows that we should multiply the middle number by 5 to get the sum.

(ii) Using the rule from part (i), we can find the middle number for a sum of 75:

Middle number = 75 ÷ 5 = 15.

The row consists of five consecutive numbers with 15 as the middle number.

The two numbers before 15 are 13 and 14.

The two numbers after 15 are 16 and 17.

Hence, the row is 13 + 14 + 15 + 16 + 17 = 75.

(iii) For a sum of 92, the middle number would have to be:

Middle number = 92 ÷ 5 = 18.4

Since the numbers in the pattern are always integers, the middle number must also be an integer. As 92 is not exactly divisible by 5 (it has a remainder of 2), there cannot be a row of this pattern that gives a sum of 92.

Hence, there will not be any row of the above pattern which gives the sum as 92.

Question 3(i)

Complete the following magic square by supplying the missing numbers :

Complete the following magic square by supplying the missing numbers. Operations on Whole Numbers, R.S. Aggarwal Mathematics Solutions ICSE Class 6.

Answer

Complete the following magic square by supplying the missing numbers. Operations on Whole Numbers, R.S. Aggarwal Mathematics Solutions ICSE Class 6.

Question 3(ii)

Complete the following magic square by supplying the missing numbers :

Complete the following magic square by supplying the missing numbers. Operations on Whole Numbers, R.S. Aggarwal Mathematics Solutions ICSE Class 6.

Answer

Complete the following magic square by supplying the missing numbers. Operations on Whole Numbers, R.S. Aggarwal Mathematics Solutions ICSE Class 6.

Question 3(iii)

Complete the following magic square by supplying the missing numbers :

Complete the following magic square by supplying the missing numbers. Operations on Whole Numbers, R.S. Aggarwal Mathematics Solutions ICSE Class 6.

Answer

Complete the following magic square by supplying the missing numbers. Operations on Whole Numbers, R.S. Aggarwal Mathematics Solutions ICSE Class 6.

Question 3(iv)

Complete the following magic square by supplying the missing numbers :

Complete the following magic square by supplying the missing numbers. Operations on Whole Numbers, R.S. Aggarwal Mathematics Solutions ICSE Class 6.

Answer

Complete the following magic square by supplying the missing numbers. Operations on Whole Numbers, R.S. Aggarwal Mathematics Solutions ICSE Class 6.
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