7/7 - 4/7 =
4/8 + 3/8 =
2/4 - 1/3 =
1/5 + 3//5 =
8/12 - 5/12=
6/9 - 3/9=
2/3 + 1/2 =
4/5
2/12
7/6
3/12
7/8
3/9
3/7
