Page 92 - Math Genius C5

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\ 08-Oct-2025 Bharat Arora Proof-9 Reader’s Sign _______________________ Date __________

( d) Convert the given fractions into their respective equivalent fractions having the
same denominator equal to the LCM of the denominators of the given fractions.

Here, the LCM of 9 and 4 is 36
4 5 67 17 67 × 4 17 × 9
Therefore, 7 – 3 = – = –
9 4 9 4 9 × 4 4 × 9

= 268 – 153 = 268 – 153 = 115 = 3 7
36 36 36 36 36

3
1
1
Example 5: A farmer uses of his land for pears, for apples and for plums. Find the
3 8 6
total area of land used to grow the fruits.
1
Solution: Area of land used for pears = , Area of land used for apples = 3
3 8
Area of land used for plums = 1
6
1
1
3
Therefore, total land used to grow the fruits = + +
3
6
8
= 1 × 8 + 3 × 3 + 1 × 4 ( as the LCM of 3, 8 and 6 is 24.)
3 × 8 8 × 3 6 × 4
7
= 8 + 9 + 4 = 8 + 9 + 4 = 21 =
24 24 24 24 24 8
7
Thus, the farmer used of the land to grow the fruits.
8
5
Example 6: What must be subtracted from 6 1 to get 3 ?
12 8
5
1
Solution: The required number is the difference obtained by subtracting 3 from 6 12 .
8
1 5 73 29 73 × 2 29 × 3
Therefore, 6 – 3 = – = – (as the LCM of 12, 8 is 24.)
12 8 12 8 12 × 2 8 × 3
146 87 146 – 87 59 11
= – = = = 2
24 24 24 24 24
11 1 5
Thus, 2 must be subtracted from 6 to get 3 .
24 12 8

practice time 4c

1. Add the following.

( a) + 3 4 ( b) 7 + 11 ( c) 3 + 7 + 1
7 7 12 12 10 20 5
3 5 1 1 5 2 1
( d) 2 + 1 ( e) 2 + 1 + ( f) 2 + 1 +
7 14 6 8 6 3 4
1 4 7 5 3 7 3 1
( g) 2 + 3 + 1 ( h) 3 + 5 + 2 ( i) 4 + 6 + 3
5 9 8 12 4 10 5 2
5 3 7 2 1 11 8 1
( j) 5 + 1 + 4 ( k) 12 + 13 + 2 (l) 1 + 3 + 1
6 8 12 5 5 14 21 7

90 Mathematics-5