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121 121 200 11 200 200 2
×
Solution: (a) 11 ÷ = 11 × Reciprocal of = 11 × = = = 18
200 200 121 121 11 11
×
×
3 5 3 5 3 8 38 32 6 1
(b) ÷ = × Reciprocal of = × = = = = 1
×
4 8 4 8 4 5 4 × 5 15 5 5
×
1 2 9 2 9 7 97 63 7
(c) 2 ÷ = × Reciprocal of = × = = = 7
×
4 7 4 7 4 2 42 8 8
Enrichment
Simplification of Fractions
We have already studied how to simplify whole numbers and integers by involving various fundamental
operations together. Here, we shall study and simplify the fractions involving various operations (+, –, ×, ÷
and of), making use of specific order.
3
Let us simplify 15+    1 of ÷ 1  − 17 .
4 4
2
8
 1 3 1 17  1 3 4 17  QReciprocalof 1 is 4 
÷
× ×
15+   2 of 4 4  − 8 =15+   2 4 1  − 8   4  
1 3 1 17× × 3 17
=15+ − =15+ − (Q LCM of 2 and 8 is 8)
2 8 2 8
−
×
×
×
15 3 17 15 8+3 4 17 1
= + − =
1 2 8 8
−
120+1217 115 3
= = =14
8 8 8
Simplify the following.


1
1
1 

(a) 3 ÷  1 − 1  2 − 1 − 1  (b) 5 −        3 of 4  ÷ 7 +   23 − 1 2 
 
+
 
4   4 2   2 4 6  7      16 5 10  12 3 3 


Practice Time 2C
1. Write the reciprocal of the following fractions:
2 4 2 5 4 3
(a) (b) (c) 2 (d) + (e) 5 ×
3 7 9 4 5 5
2. Divide the following fractions:
2 2 2
(a) 5 ÷ (b) ÷ 6 (c) 1 ÷ 2
3 15 5
1 3 1
(d) 2 ÷ 15 (e) 15 2÷ (f) 36 1÷
7 5 17
3. Find the quotient.

4 7 1 7 2 1 1 7
(a) ÷ (b) 2 ÷ (c) 6 ÷ 4 (d) 13 ÷
3 5 7 2 3 5 6 21
1 1 1 1 5 1
(e) 7 ÷ 8 (f) 3 ÷ 4 (g) 2 ÷ 8
8 16 4 28 8 6

Mathematics-7 40