1/2 - 1/3 =
8/15 + 2/4 =
2/3 - 1/4 =
2/4 + 2/5
2/4+ 1/3 =
1/2 + 1/3 =
3/6 -2/8=
5/12
9/10
4
31/30
5/6
1/6
