Page 92 - Math Skill - 5

90 Maths

Write them in column and then add.
Challenge
1 2 1 I’m a number between whole ones,
3 . 0 4 0 so small yet precise,
1 2 . 5 0 0 In between the spaces where the whole
3 . 6 8 7 numbers rise.
+ 1 2 4 . 9 5 0 I’m not a fraction, but I’m a part, you see,
1 4 4 . 1 7 7 With dots and digits, you’ll find me.
What am I?
Example 2: Subtract 13.75 from 80.

Solution: Converting the given numbers into like decimals, 13.75; 80 → 80.00
Now, write them in column and then subtract.

7 9 9 10
8 0 . 0 0
– 1 3 . 7 5
6 6 . 2 5

Example 3: Simplify: 35.7 – 16.3 + 124.28 – 36.58.
Solution: Writing each of the given decimals with two decimal places, we get

35.70 – 16.30 + 124.28 – 36.58
Adding positive numbers and negative numbers separately

3 5 . 7 0 1 6 . 3 0
+ 1 2 4 . 2 8 + 3 6 . 5 8
1 5 9 . 9 8 5 2 . 8 8

Now, 1 5 9 . 9 8
– 5 2 . 8 8
1 0 7 . 1 0

Hence, 35.7 – 16.3 + 124.28 – 36.58 = 107.10

Exercise 6.5

1. Add the following.
(a) 18.4 + 3.006 (b) 2.375 + 8.105 (c) 18.07 + 13.008

2. Find the sum.
(a) 312.5 + 93.27 + 127.35 + 2.8 (b) 63.5 + 237.05 + 1.005 + 12.0505

3. Find the difference.
(a) 18.04 – 3.63 (b) 90.02 – 19.20 (c) 537.203 – 38.199
(d) 100.005 – 28.193 (e) 500.34 – 219.04 (f) 1000.09 – 29.94
4. Subtract the following.
(a) 3.78 from 16 (b) 81.6 from 93.25 (c) 16.764 from 35.67