Page 71 - Math Skill - 5

Fractions 69

LCM of 3, 6 and 12 is 12.

74× = 28 19 2× = 38 and 17 [Convert into like fractions]
,
34× 12 62× 12 12

28 + 38 − 17 = 28 38 17+ − = 66 17− = 49 = 4 1

12 12 12 12 12 12 12

Exercise 5.5

1. Add the following.
1 1 16 2 2 2 1 1
(a) + (b) + (c) 1 + 3 (d) 5 + 3 + 4
2 3 17 17 3 15 8 12
2. Subtract the following.

(a) 5 1 from 7 2 (b) 4 1 from 6 2 (c) 2 1 from 3 (d) 7 from 1 11
6 3 9 3 8 8 24
3. Solve the following.
5 1 5 3 1 1 5 7 4
(a) + + (b) 3 + 2 (c) 4 + + (d) −
18 6 12 7 6 4 6 18 15
4. Simplify the following.

5 1 3 1 3 7 2 1
(a) 3 + 2 − 1 (b) 712 − 8 (c) + 8 − 1
+
24 16 12 3 7 10 5 2

Word Problems

Let’s Attempt

7 1
Example 1: A board 2 cm thick is glued to another board of thickness 3 cm. What is the
16 8
combined thickness of the boards?

7 39
Solution: Thickness of one board = 2 cm = cm
16 16

1
Thickness of another board = 3 cm = 25 cm
8 8
39 25 Fact-o-meter
Combined thickness of boards = +
16 8 When we add or subtract

(39 1× ) (252+ × ) 39 50+ 89 9 their units must be same.
= = = = 5 cm
16 16 16 16

9
Hence, thickness of combined board is 5 cm.
16