3/4 - 1/6 = 9/12 - 2/12 = 7/12
11/12 + 9/10 = 55/60 + 54/60 = 109/60 = 1 49/60
5/6 + 3/8 - 1/3 = 20/24 + 9/24 - 8/24 = 21/24 = 7/8