6 1/9 - 4 8/9 = 55/9 - 44/9 = 11/9 = 1 2/9
8 3/7 - 4 4/7 = 59/7 - 32/7 = 27/7 = 3 6/7
(1 1/8 + 8 5/8) - 3 2/8 = 9 6/8 - 3 2/8 = 6 4/8 = 6 1/2
4 8/11 - (5 2/11 - 3 7/11) = 4 8/11 - (57/11 - 40/11) = 4 8/11 - 17/11 = 4 8/11 - 1 6/11 = 3 2/11
16 10/11 - (1 4/11 + 7 9/11) = 16 10/11 - 9 2/11 = 7 8/11