Ответ:

1 3 5/6 + (-5/6 - 1/7) = 7/3

1. -5/6 - 1/7 =-41/42
2. 23/6 + (-41/42) = -18/42 = 7/3

2 3/8 - (1/9 - 5\8) = 8/9

1. 1/9 - 5/8 = -37/72
2. 3/8 - (-37/72) = 64/72 = 8/9