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This activity is about adding and subtracting fractions with different denominators.
Example
When adding or subtracting fractions we begin by finding the lowest common multiple (LCM) of both denominators.
Solve 9/24 - 8/15
First find the LCM of 24 and 15.
| 24 | 48 | 96 | 120 | ... | ||||
| 15 | 30 | 45 | 60 | 75 | 90 | 105 | 120 | ... |
The LCM is 120.
120 = 5 x 24
and
120 = 8 x 15
| 19 | - | 8 | = | 19 x 5 | - | 8 x 8 | = | 95 - 64 | = | 31 |
| 24 | 15 | 24 x 5 | 15 x 8 | 120 | 120 |
Answers in this activity should be given as reduced fractions.
