Page 70 - Math Skill - 5

68 Maths

7 + 23 + 16
5 10 5

LCM of 5, 10 and 5 is 10.

72× = 14 23 1 = 23 16 2× = 32
×
,
,
52× 10 10 1 10 52× 10
×
14 + 23 + 32 = 14 23 32+ +
10 10 10 10

69 9
= = 6
10 10

2 4
Example 4: Subtract: 3 − 1
11 11
2 3112× + 33 2+ 35
Solution: 3 = = = Alternative Approach
11 11 11 11  −  2

1 4 = 1114× + = 11 4+ = 15 (3 – 1) +  2 − 4  = 2 +  


 11


11 11 11 11 11 11
−
35 15 35 15 20 9 2 22 2− 20 9
− = = = 1 = 2 – = = = 1
11 11 11 11 11 11 11 11 11
Example 5: Simplify.
1
1
1
(a) 4 − 5 + (b) 2 + 3 − 1 5
9 12 2 3 6 12
4 5 1
Solution: (a) − +
9 12 2
LCM of 9, 12 and 2 is 36.

×
44 = 16 , 53× = 15
94× 36 12 3× 36

118× 18
and = (Convert unlike fractions to like fractions)
218× 36

16 − 15 + 18 = 16 15 18− + = 34 15− = 19
36 36 36 36 36 36

1
1
(b) 2 + 3 − 1 5
3 6 12
7 19 17
= + − (converting them into improper fractions)
3 6 12