SChand Composite Mathematics Class 7 Chapter 3 Decimals Exercise 3C

 Exercise 3C

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Q1 | Ex-3C | Class 8 | Decimals |S.Chand | Composite Mathematics | Chapter 3 | myhelper

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Question 1

(i) 8.45÷10

Sol :

$=\frac{845}{10}\times \frac{1}{10}=\frac{845}{100}$

=0.845

(ii) 39÷10

Sol :

$=\frac{39}{10}$

=3.9

(iii) 0.039÷10

Sol :

$=\frac{39}{1000}\times \frac{1}{10}$

=0.0039

(iv) 15.9÷10

Sol :

=1.59

(v) 537÷100

Sol :

=5.37

(vi) 9.7÷100

Sol :

=0.097

(vii) 76÷1000

Sol :

=0.076

(viii) 80÷10000

Sol :

=0.0080

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Q2 | Ex-3C | Class 8 | Decimals |S.Chand | Composite Mathematics | Chapter 3 | myhelper

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Question 2

(i) 0.6÷2

Sol :

=0.3

(ii) 29.4÷7

Sol :

=4.2

(iii) 0.063÷3

Sol :

=0.021

(iv) 1.232÷4

Sol :

=0.308

(v) 0.00037÷5

Sol :

=0.000074

(vi) 1026.76÷38

Sol :

=27.02

(vii) 20.202÷74

Sol :

=0.273

(viii) 11.2575÷114

Sol :

=0.09875

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Q3 | Ex-3C | Class 8 | Decimals |S.Chand | Composite Mathematics | Chapter 3 | myhelper

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Question 3

Divide :-

(i) 0.0000684 by 0.04

Sol :

$=\frac{684}{10000000}\div \frac{4}{100}=\frac{684}{100000}\times \frac{1}{4}$

$=\frac{171}{100000}$

=0.00171

(ii) 315.84 by 4.7

Sol :

$=\frac{31584}{100} \div \frac{47}{10}=\frac{31584}{10} \times \frac{1}{47}$

$=\frac{672}{10}$

=67.2

(iii) 3.154 by 1.25

Sol :

$=\frac{3154}{1000}\div \frac{125}{100}=\frac{3154}{1000}\times \frac{100}{125}$

$=\frac{3154}{10}\times \frac{1}{125}$

=2.5232

(iv) 0.79765 by 3.71

Sol :

$=\frac{79765}{100000} \div \frac{371}{100}=\frac{79765}{100000} \times \frac{100}{371}$

$=\frac{79765}{1000} \times \frac{1}{371}$

$=\frac{215}{1000}$

=0.215

(v) 18.21 by 0.003

Sol :

$=\frac{1821}{100} \div \frac{3}{1000}=\frac{1821}{100} \times \frac{1000}{3}$

$=\frac{607}{1} \times \frac{10}{1}$

=6070

(vi) 543.213 by 3.1

Sol :

$=\frac{543213}{1000} \div \frac{31}{10}=\frac{543213}{100} \times \frac{1}{31}$

$=\frac{17,523}{100}$

=175.23

(vii) 15.3 by 0.00017

Sol :

$=\frac{153}{10} \div \frac{17}{100000}=\frac{153}{1} \times \frac{17}{10000}$

=9×10000

=90000

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Q4 | Ex-3C | Class 8 | Decimals |S.Chand | Composite Mathematics | Chapter 3 | myhelper

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Question 4

Calculate , giving your answer correct to the individual number of decimal place:

(i) 0.754÷3 to 1 decimal place

Sol :

0.251≅0.3

(ii) 24.71÷13 to 3 decimal place

Sol :

=1.900

(iii) 16.7÷6 to 2 decimal place

Sol :

2.783≅2.78

(iv) 84÷0.7 to 3 decimal place

Sol :

$=\frac{84}{0.7} \times \frac{10}{10}=\frac{840}{7}$

=120

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Q5 | Ex-3C | Class 8 | Decimals |S.Chand | Composite Mathematics | Chapter 3 | myhelper

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Question 5

Give the following fractions as decimal correct to 3 decimal places:

(i) $\frac{1}{6}$

Sol :

0.166

(ii) $\frac{3}{11}$

Sol :

0.272

(iii) $\frac{7}{18}$

Sol :

(iv) $\frac{8}{55}$

Sol :

(v) $\frac{19}{24}$

Sol :