Adding and subtracting fractions with unlike denominators
Answers are for parents and teachers.
1
Work out 3/8 + 1/6 and 5/6 + 1/9.
9/24 + 4/24 = 13/24. And 15/18 + 2/18 = 17/18.
2
Work out 7/10 − 1/4.
14/20 − 5/20 = 9/20.
3
Work out 5/6 + 7/12 and write the answer as a mixed number.
10/12 + 7/12 = 17/12 = 1 5/12.
4
A garden bed has 1/3 roses and 1/4 jasmine, and the rest is grass. What fraction is grass?
1/3 + 1/4 = 4/12 + 3/12 = 7/12. Grass: 1 − 7/12 = 5/12.
5
Farida says 1/2 + 1/3 = 2/5 because she adds the tops and the bottoms. Show her mistake and give the right answer.
2/5 is less than 1/2, but a sum must be greater than either part. The right way is 3/6 + 2/6 = 5/6.