Decimal Fractions — Multiple Choice Questions

2.73 + 27.30 is equal to:

1. 30.03

2. 275.73

3. 30

4. none of these

Answer

To add decimal numbers, we write them as like decimals and then add. Here both numbers already have 2 decimal places.

$\begin{array}{rr} & 2.73 \\ + & 27.30 \\ \hline & 30.03 \end{array}$

2.73 + 27.30 = 30.03

Hence, option 1 is the correct option.

27.3 - 2.73 is equal to:

1. 30.03

2. 24.57

3. 2.45

4. none of these

Answer

To subtract decimal numbers, we first make them like decimals. Writing 27.3 as 27.30, now both numbers have 2 decimal places, and then we subtract.

$\begin{array}{rr} & 27.30 \\ - & 2.73 \\ \hline & 24.57 \end{array}$

27.30 - 2.73 = 24.57

Hence, option 2 is the correct option.

0.058 × 10000 is equal to:

1. 0.0000058

2. 58

3. 580

4. 5800

Answer

On multiplying a decimal number by 10, 100, 1000, 10000, etc., the decimal point shifts to the right by as many places as there are zeroes in the multiplier. Since 10000 has 4 zeroes, the decimal point shifts 4 places to the right.

0.058 × 10000 = 580

Hence, option 3 is the correct option.

5.8 ÷ 100 is equal to:

1. 5.800

2. 5800

3. 0.58

4. 0.058

Answer

On dividing a decimal number by 10, 100, 1000, etc., the decimal point shifts to the left by as many places as there are zeroes in the divisor. Since 100 has 2 zeroes, the decimal point shifts 2 places to the left.

5.8 ÷ 100 = 0.058

Hence, option 4 is the correct option.

0.2 × 0.02 × 0.002 × 1000 is equal to:

1. 8

2. 0.08

3. 0.008

4. 0.8

Answer

To multiply decimal numbers, we multiply them ignoring the decimal points and then mark the decimal point so that the number of decimal places in the product equals the sum of the decimal places of the numbers multiplied.

0.2 × 0.02 × 0.002 = 0.000008

Now, multiplying by 1000 shifts the decimal point 3 places to the right.

0.000008 × 1000 = 0.008

Hence, option 3 is the correct option.

₹ 66 + 6 paise in rupees is equal to:

1. ₹ 72

2. ₹ 66.6

3. ₹ 66.06

4. none of these

Answer

Since 100 paise = ₹ 1, we first convert the paise into rupees by dividing by 100, and then add.

6 paise = ₹ 0.06

∴ ₹ 66 + ₹ 0.06 = ₹ 66.06

Hence, option 3 is the correct option.

Area of a square is 0.25 m²; its perimeter is:

1. 20 m

2. 2 m

3. 0.2 m

4. 0.4 m

Answer

Area of square = (side)² = 0.25 m²

∴ Side = $\sqrt{0.25}$ = 0.5 m

Perimeter = 4 × side = 4 × 0.5 = 2 m

Hence, option 2 is the correct option.

Cost of 5 identical articles is ₹ 22.50, then the cost of 15 such articles is:

1. ₹ 22.50 × 3

2. ₹ 2.25 × 3

3. ₹ 22.50 × 15

4. ₹ 22.50 × 5

Answer

15 articles = 3 × 5 articles

∴ Cost of 15 articles = 3 × (cost of 5 articles) = ₹ 22.50 × 3

Hence, option 1 is the correct option.

$\dfrac{1}{100} + \dfrac{1}{1000} + \dfrac{1}{10000}$ is equal to:

1. 0.111

2. 1.11

3. 0.0111

4. 11.1

Answer

We first change each fraction into a decimal fraction and then add them as like decimals.

$\dfrac{1}{100} = 0.01, \dfrac{1}{1000} = 0.001 \text { and } \dfrac{1}{10000}$ = 0.0001

∴ 0.0100 + 0.0010 + 0.0001 = 0.0111

Hence, option 3 is the correct option.

75 g in kg is equal to:

1. 0.75 kg

2. 0.750 kg

3. 0.7500 kg

4. 0.075 kg

Answer

Since 1000 g = 1 kg, we convert grams into kilograms by dividing by 1000.

75 g = $\dfrac{75}{1000}$ kg = 0.075 kg

Hence, option 4 is the correct option.