
Unit 7: Numeracy skills
Fractions
Subtracting fractions
This works in the same way as addition. If the denominators are the same, simply subtract along the top line:
5 | - | 3 | = | 5 | - | 3 | = | 2 | = | 1 x 2 | = | 1 | ||||
- | - | ------- | - | ------ | - | |||||||||||
6 | 6 | 6 | 6 | 3 x 2 | 3 |
12 | - | 1 | = | 12 | - | 3 | x | 1 | = | 12 | - | 3 | = | 1 | 2 | - | 3 | = | 9 | ||
--- | - | --- | ------ | --- | ---- | ------------ | ----- | ||||||||||||||
15 | 5 | 15 | 3 | x | 5 | 15 | 1 | 5 | 1 | 5 | 1 | 5 |
Cancelling down gives:
9 | = | 3 | x | 3 | = | 3 | |
---- | ------ | - | |||||
1 | 5 | 3 | x | 5 | 5 |
An alternative method would have been to cancel down 12 / 15 to 4 / 5 initially leaving an easier sum 4 / 5 – 1 / 5 = 3 / 5
SMILE - Numeracy skills by Tom Frank, Eric Williams and Clare Wright, University of Birmingham Careers Centre adapted by Marion Kelt Glasgow Caledonian University is licensed under a Creative Commons Attribution 3.0 Unported License.