Page 48 - ICSE Math 7

14.05
(b) 8 112.4 Alternative method:
–8 1124 1
32 112.4 ÷ 8 = 10 × 8
–32 281 × 5
40 (Adding 0 on the right = 20 × 5
–40 side to complete division) 1405
× = 100

So, 112.4 ÷ 8 = 14.05 = 14.05

Division of a decimal number by a decimal number
Remove the decimal point of the divisor and make it a natural number. To do so, shift the decimal
point in the dividend to the right as many places as the number of decimal places in the divisor. Now,
do the division as in the previous case.

Example 11: Divide.
(a) 59.01 by 2.1 (b) 37.575 by 0.15
Solution: (a) Shift the decimal point of the dividend (b) Shift the decimal point of the
59.01 by one place to the right to dividend 37.575 by two places to the
make 2.1 a natural number. right to make 0.15 a natural number.
59.01 × 10 = 590.1 37.575 × 100 = 3757.5
2.1 × 10 21 0.15 × 100 15
Now, do 590.1 ÷ 21 Now, do 3757.5 ÷ 15
28.1 250.5
21 590.1 15 3757.5
–42 –30
170 75
–168 –75
21 75
–21 –75
× ×

So, 59.01 ÷ 2.1 = 28.1 So, 37.575 ÷ 0.15 = 250.5

Division of a decimal number by powers of 10
When dividing a decimal number by 10, 100, 1,000, etc., just shift the decimal point of the dividend
to the left as many places as there are number of zeros in the divisor. If required, add zeros to the left
of the dividend.
Example 12: Divide.

(a) 3.59 by 10 (b) 25.29 by 1,000 (c) 0.9 by 100
Solution: (a) 3.59 ÷ 10 = 0.359 (As the number of zeros in 10 is 1, shift decimal point 1 place
to the left)
(b) 25.29 ÷ 1,000 = 0.02529 (Add 1 zero to the left so that the decimal point can be
shifted 3 places)

(c) 0.9 ÷ 100 = 0.009 (Add 2 zeros to the left so that the decimal point can be shifted
2 places)

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