fractions test

2/5 - 1/4

3/20

3/5 - 1/2

1/10

2/3 - 2/10

7/15

1/10 + 1/2

3/5

2/3 + 3/4

1 5/12

3/5 + 1/2

1 1/10

1/2 + 1/4

3/4

6/10 - 1/3

4/15

1/2 - 2/4

0

1/2 + 1/3

5/6

3/4 + 1/2

1 1/4

1/5 + 1/4

9/20