5/6 - 3/4 = (10 - 9) / 12 = 1/12
1/3 +1/5 = 5/15 + 3/15 = 8/15
3/10 + 1/2 = 3/10 + 5/10 = 8/10 = 4/5
1/3 - 1/7 = 7/21 - 3/21 = 4/21
2/9 + 0 = 2/9
9/20 + 3/8 = 18/40 + 15/40 = 33/40
19/75 - 11/50 = 38/150 - 33/150 = 5/150 = 1/30
11/14 + 18/21 = 33/42 + 36/42 = 69/42 = 1 27/42 = 1 9/14
7/15 - 0 = 7/15