NCERT Solutions Class 7 Maths Chapter 2 Fractions and Decimals Ex 2.7

NCERT Solutions Class 7 Mathematics 
Chapter – 2 (Fractions and Decimals)

The NCERT Solutions in English Language for Class 7 Mathematics Chapter – 2 Fractions and Decimals Exercise 2.7 has been provided here to help the students in solving the questions from this exercise. 

Chapter : 2 Fractions and Decimals

Exercise – 2.7

1. Find:
(i) 0.4 ÷ 2                  (ii) 0.35 ÷ 5                   (iii) 2.48 ÷ 4                             (iv) 65.4 ÷ 6
(v) 651.2 ÷ 4             (vi) 14.49 ÷ 7                (vii) 3.96 ÷ 4                             (viii) 0.80 ÷ 5
Solution –
(i) 0.4 ÷ 2
= \frac{4}{10} ÷ 2

= \frac{4}{10} × \frac{1}{2} = \frac{2}{10}
On dividing a decimal by 10, the decimal point is shifted to the left by one place.
Then, = 0.2

(ii) 0.35 ÷ 5

= \frac{35}{100} ÷ 5

= \frac{35}{100} × \frac{1}{5} = \frac{7}{100}
On dividing a decimal by 100, the decimal point is shifted to the left by two places.
Then, = 0.07

(iii) 2.48 ÷ 4

= \frac{248}{100} ÷ 4

= \frac{248}{100} × \frac{1}{4} = \frac{62}{100}
On dividing a decimal by 100, the decimal point is shifted to the left by two places.
Then, = 0.62

(iv) 65.4 ÷ 6

= \frac{654}{10}  ÷ 6

= \frac{654}{10} × \frac{1}{6} = \frac{109}{10}
On dividing a decimal by 10, the decimal point is shifted to the left by one place.
Then, = 10.9

(v) 651.2 ÷ 4

= \frac{6512}{10} ÷ 4

= \frac{6512}{10} × \frac{1}{4} = \frac{1628}{10}
On dividing a decimal by 10, the decimal point is shifted to the left by one place.
Then, = 162.8

(vi) 14.49 ÷ 7

= \frac{1449}{100} ÷ 7

= \frac{1449}{100} × \frac{1}{7} = \frac{207}{100}
On dividing a decimal by 100, the decimal point is shifted to the left by two places.
Then, = 2.07

(vii) 3.96 ÷ 4

= \frac{396}{100} ÷ 4

= \frac{396}{100} × \frac{1}{4} = \frac{99}{100}
On dividing a decimal by 100, the decimal point is shifted to the left by two places.
Then, = 0.99

(viii) 0.80 ÷ 5

= \frac{80}{100} ÷ 5

= \frac{80}{100} × \frac{1}{5} = \frac{16}{100}
On dividing a decimal by 100, the decimal point is shifted to the left by two places.
Then, = 0.16

2. Find:
(i) 4.8 ÷ 10              (ii) 52.5 ÷ 10                (iii) 0.7 ÷ 10                (iv) 33.1 ÷ 10
(v) 272.23 ÷ 10      (vi) 0.56 ÷ 10               (vii) 3.97 ÷10

Solution –
(i) 4.8 ÷ 10
On dividing a decimal by 10, the decimal point is shifted to the left by one place.
= 0.48

(ii) 52.5 ÷ 10
On dividing a decimal by 10, the decimal point is shifted to the left by one place.
= 5.25

(iii) 0.7 ÷ 10
On dividing a decimal by 10, the decimal point is shifted to the left by one place.
= 0.07

(iv) 33.1 ÷ 10
On dividing a decimal by 10, the decimal point is shifted to the left by one place.
= 3.31

(v) 272.23 ÷ 10
On dividing a decimal by 10, the decimal point is shifted to the left by one place.
= 27.223

(vi) 0.56 ÷ 10
On dividing a decimal by 10, the decimal point is shifted to the left by one place.
= 0.056

(vii) 3.97 ÷10
On dividing a decimal by 10, the decimal point is shifted to the left by one place.
= 0.397

3. Find:
(i) 2.7 ÷ 100                       (ii) 0.3 ÷ 100                       (iii) 0.78 ÷ 100
(iv) 432.6 ÷ 100                (v) 23.6 ÷ 100                     (vi) 98.53 ÷ 100

Solution –
(i) 2.7 ÷ 100
On dividing a decimal by 100, the decimal point is shifted to the left by two places.
= 0.027

(ii) 0.3 ÷ 100
On dividing a decimal by 100, the decimal point is shifted to the left by two places.
= 0.003

(iii) 0.78 ÷ 100
On dividing a decimal by 100, the decimal point is shifted to the left by two places.
= 0.0078

(iv) 432.6 ÷ 100
On dividing a decimal by 100, the decimal point is shifted to the left by two places.
= 4.326

(v) 23.6 ÷100
On dividing a decimal by 100, the decimal point is shifted to the left by two places.
= 0.236

(vi) 98.53 ÷ 100
On dividing a decimal by 100, the decimal point is shifted to the left by two places.
= 0.9853

4. Find:
(i) 7.9 ÷ 1000                        (ii) 26.3 ÷ 1000                   (iii) 38.53 ÷ 1000
(iv) 128.9 ÷ 1000                 (v) 0.5 ÷ 1000

Solution –
(i) 7.9 ÷ 1000
On dividing a decimal by 1000, the decimal point is shifted to the left by three places.
= 0.0079

(ii) 26.3 ÷ 1000
On dividing a decimal by 1000, the decimal point is shifted to the left by three places.
= 0.0263

(iii) 38.53 ÷ 1000
On dividing a decimal by 1000, the decimal point is shifted to the left by three places.
= 0.03853

(iv) 128.9 ÷ 1000
On dividing a decimal by 1000, the decimal point is shifted to the left by three places.
= 0.1289

(v) 0.5 ÷ 1000
On dividing a decimal by 1000, the decimal point is shifted to the left by three places.
= 0.0005

5. Find:
(i) 7 ÷ 3.5                            (ii) 36 ÷ 0.2                    (iii) 3.25 ÷ 0.5                             (iv) 30.94 ÷ 0.7
(v) 0.5 ÷ 0.25                    (vi) 7.75 ÷ 0.25              (vii) 76.5 ÷ 0.15                          (viii) 37.8 ÷ 1.4
(ix) 2.73 ÷ 1.3

Solution –
(i) 7 ÷ 3.5

= 7 ÷ \frac{35}{10}

= 7 × \frac{10}{35} = 1 × \frac{10}{5} = 2

(ii) 36 ÷ 0.2

= 36 ÷ \frac{2}{10} 

= 36 × \frac{10}{2} = 18 × 10 = 180

(iii) 3.25 ÷ 0.5

= \frac{325}{100} ÷ \frac{5}{10}

= \frac{325}{100} × \frac{10}{5}

= \frac{325}{10} × \frac{1}{5} = \frac{65}{10} = 6.5

(iv) 30.94 ÷ 0.7

= \frac{3094}{100} ÷ \frac{7}{10}

= \frac{3094}{100} × \frac{10}{7}

= \frac{3094}{10} × \frac{1}{7}  = \frac{442}{10} = 44.2

(v) 0.5 ÷ 0.25

= \frac{5}{10} ÷ \frac{25}{100}

= \frac{5}{10} × \frac{100}{25} = \frac{10}{5} = 2

(vi) 7.75 ÷ 0.25

= \frac{775}{100}  ÷ \frac{25}{100}

= \frac{775}{100} × \frac{100}{25} = \frac{775}{25} = 31

(vii) 76.5 ÷ 0.15

= \frac{765}{10} ÷ \frac{15}{100}

= \frac{765}{10} × \frac{100}{15} = 51 × 10 = 510

(viii) 37.8 ÷ 1.4

= \frac{378}{10} ÷ \frac{14}{10}

= \frac{378}{10} × \frac{10}{14} = \frac{378}{14} = 27

(ix) 2.73 ÷ 1.3

= \frac{273}{100} ÷ \frac{13}{10}

= \frac{273}{100} × \frac{10}{13}  = \frac{21}{10} = 2.1

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

Solution –
Total distance covered by vehicle in 2.4 liters of petrol = 43.2 km
∴ Distance covered in 1 liter of petrol = 43.2 ÷ 2.4

= \frac{432}{10} ÷ \frac{24}{10}

= \frac{432}{10} × \frac{10}{24}

= \frac{432}{24} = 18 km
∴ Total distance covered in 1 liter of petrol is 18 km.

 

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