Subtracting fractions uses the same idea as adding. First give both fractions a common denominator, then subtract the numerators and keep the denominator.
For 4/5 − 1/3, use 15: 4/5 = 12/15 and 1/3 = 5/15. Then 12/15 − 5/15 = 7/15. In a word problem, subtraction often answers how much is left or how much more one amount is than another.
With mixed numbers, you may need to exchange a whole for a fraction first, just like exchanging a ten.
Worked example
5/6 − 1/4 =
- Common denominator 12: 5/6 = 10/12 and 1/4 = 3/12.
- 10/12 − 3/12 = 7/12.
Answer:7/12
Key words
- difference
- the answer to a subtraction
- common denominator
- a shared bottom number
- numerator
- the top number
Practise this
New questions every time.
Common Core-referenced: 5.NF.A.1, 5.NF.A.2