Fractions and Decimals

CBSE Class –VII Mathematics
NCERT Solutions
Chapter 2 Fractions and Decimals (Ex. 2.7)

Question 1. Find:

(i) 0.4

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2
(ii) 0.35

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5
(iii) 2.48

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4
(iv) 65.4

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6
(v) 651.2

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4
(v) 14.49

\div

7
(vii) 3.96

\div

4
(viii) 0.80

\div

Answer: (i) 0.4

\div

2 =

\frac{4}{10} \times \frac{1}{2} = \frac{2}{10}

= 0.2

(ii) 0.35

\div

5 =

\frac{35}{100} \times \frac{1}{5} = \frac{7}{100}

= 0.07

(iii)2.48

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4 =

\frac{248}{100} \times \frac{1}{4} = \frac{62}{100}

= 0.62

(iv) 65.4

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6 =

\frac{654}{10} \times \frac{1}{6} = \frac{109}{10}

= 10.9

(v) 651.2

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4 =

\frac{6512}{10} \times \frac{1}{4} = \frac{1628}{10}

= 162.8

(vi)14.49

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7 =

\frac{1449}{100} \times \frac{1}{7} = \frac{207}{100}

= 2.07

(vii)3.96

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4 =

\frac{396}{100} \times \frac{1}{4} = \frac{99}{100}

= 0.99

(viii)0.80

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5 =

\frac{80}{100} \times \frac{1}{5} = \frac{16}{100}

= 0.16

Question 2. Find:

(i) 4.8

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(ii) 52.5

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(iii) 0.7

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(iv) 33.1

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(v) 272.23

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(vi) 0.56

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(vii) 3.97

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Answer: (i) 4.8

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10 =

\frac{4.8}{10}

= 0.48

(ii) 52.5

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10 =

\frac{52.5}{10}

= 5.25

(iii) 0.7

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10 =

\frac{0.7}{10}

= 0.07

(iv) 33.1

\div

10 =

\frac{33.1}{10}

= 3.31

(v) 272.23

\div

10 =

\frac{272.23}{10}

= 27.223

(vi) 0.56

\div

10 =

\frac{0.56}{10}

= 0.056

(vii) 3.97

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10 =

\frac{3.97}{10}

= 0.397

Question 3. Find:

(i) 2.7

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100

(ii) 0.3

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100

(iii) 0.78

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100

(iv) 432.6

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100

(v) 23.6

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100

(vi) 98.53

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100

Answer: (i) 2.7

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100 =

\frac{27}{10} \times \frac{1}{100} = \frac{27}{1000}

= 0.027

(ii) 0.3

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100 =

\frac{3}{10} \times \frac{1}{100} = \frac{3}{1000}

= 0.003

(iii) 0.78

\div

100 =

\frac{78}{100} \times \frac{1}{100} = \frac{78}{10000}

= 0.0078

(iv) 432.6

\div

100 =

\frac{4326}{10} \times \frac{1}{100} = \frac{4326}{1000}

= 4.326

(v) 23.6

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100 =

\frac{236}{10} \times \frac{1}{100} = \frac{236}{1000}

= 0.236

(vi) 98.53

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100 =

\frac{9853}{100} \times \frac{1}{100} = \frac{9853}{10000}

0.9853

Question 4. Find:

(i) 7.9

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1000

(ii) 26.3

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1000

(iii) 38.53

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1000

(iv) 128.9

\div

1000

(v) 0.5

\div

1000

Answer: (i) 7.9

\div

1000 =

\frac{79}{10} \times \frac{1}{1000} = \frac{79}{10000}

= 0.0079

(ii) 26.3

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1000 =

\frac{263}{10} \times \frac{1}{1000} = \frac{263}{10000}

= 0.0263

(iii) 38.53

\div

1000 =

\frac{3853}{100} \times \frac{1}{1000} = \frac{3853}{100000}

= 0.03853

(iv) 128.9

\div

1000 =

\frac{1289}{10} \times \frac{1}{1000} = \frac{1289}{10000}

= 0.1289

(v) 0.5

\div

1000 =

\frac{5}{10} \times \frac{1}{1000} = \frac{5}{10000}

= 0.0005

Question 5. Find:

(i) 7

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3.5

(ii) 36

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0.2

(iii) 3.25

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0.5

(iv) 30.94

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0.7

(v) 0.5

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0.25

(vi) 7.75

\div

0.25

(vii) 76.5

\div

0.15

(viii) 37.8

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1.4

(ix) 2.73

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1.3

Answer: (i) 7

\div

3.5 =

7 \div \frac{35}{10} = 7 \times \frac{10}{35} = \frac{10}{5}

= 2

(ii) 36

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0.2 =

36 \div \frac{2}{10} = 36 \times \frac{10}{2} =

18 x 10 = 180

(iii) 3.25

\div

0.5 =

\frac{325}{100} \div \frac{5}{10} = \frac{325}{100} \times \frac{10}{5} = \frac{65}{10}

= 6.5

(iv) 30.94

\div

0.7 =

\frac{3094}{100} \div \frac{7}{10} = \frac{3094}{100} \times \frac{10}{7} = \frac{442}{10}

= 44.2

(v) 0.5

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0.25 =

\frac{5}{10} \div \frac{25}{100} = \frac{5}{10} \times \frac{100}{25} = \frac{10}{5}

= 2

(vi) 7.75

\div

0.25 =

\frac{775}{100} \div \frac{25}{100} = \frac{775}{100} \times \frac{100}{25}

= 31

(vii) 76.5

\div

0.15 =

\frac{765}{10} \div \frac{15}{100} = \frac{765}{10} \times \frac{100}{15}

= 51 x 10 = 510

(viii) 37.8

\div

1.4 =

\frac{378}{10} \div \frac{14}{10} = \frac{378}{10} \times \frac{10}{14}

= 27

(ix) 2.73

\div

1.3 =

\frac{273}{100} \div \frac{13}{10} = \frac{273}{100} \times \frac{10}{13} = \frac{21}{10}

= 2.1

Question 6. A vehicle covers a distance of 43.2 km in 2.4 litres of petrol. How much distance will it cover in one litre petrol?

Answer:

∵

In 2.4 litres of petrol, distance covered by the vehicle = 43.2 km

∴

In 1 litre of petrol, distance covered by the vehicle = 43.2

\div

2.4

\frac{432}{10} \div \frac{24}{10}

\frac{432}{10} \times \frac{10}{24}

Fractions and Decimals - Solutions 7