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