5/6 + 4/6 =
11/5 - 3/5 =
5/14
7/11
7/12 + 2/12 =
7/14 -2/14 =
9/12
16/9
9/11 - 2/11=
8/10
5/9 + 11/9 =
17/10 - 9/10 =
8/5
9/6
