Page 96 - ICSE Math 6

9. Write the following fractions as decimals.

7 17 97 132
(a) (b) (c) (d)
5 2 20 50

111 1 1 5
(e) (f) 30 (g) 10 (h) 7
125 125 10 8

10. Write the following decimals as fractions.
(a) 0.8 (b) 0.22 (c) 9.212 (d) 13.13
(e) 2.088 (f) 10.06 (g) 18.902 (h) 125.512

Fundamental Operations on Decimals

Addition of decimals
Convert all the decimals into like decimals. Write the decimals to be added one below the other with
the decimal points in line and the corresponding digits in the same column. Now, do the usual addition
and place the decimal point vertically below the other decimal points in the sum.

Example 7: Add the following.
(a) 21.11 and 470.205 (b) 73.652, 72.01 and 0.065

Solution: (a) 021.110 (Converting to (b) 73.652 (Converting to
+ 470.205 like decimals) 72.010 like decimals)
491.315 + 00.065
145.727

Subtraction of decimals
Convert all the decimals into like decimals. Write the smaller number below the bigger number with
the decimal points in line. Now, do the usual subtraction and place the decimal point vertically below
the other decimal points in the difference.
Example 8: Subtract.

(a) 15.99 from 20.5 (b) 115.251 from 222

Solution: (a) 20.50 (Converting to (b) 222.000 (Converting to
– 15.99 like decimals) – 115.251 like decimals)
04.51 106.749

Example 9: Simplify: 19.586 + 0.009 – 4.719 – 2.05
Solution: After converting to like decimals, After converting to like decimals,
add all the positive numbers add all the negative numbers
together to get: together to get:
19.586 – 4.719
+ 00.009 – 2.050

19.595 – 6.769

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