What is the answer for 2 5/7 - 7/8

Change the mixed leading number into an improper fraction ... a b/c = (ac+b) / c

19/7-7/8 the least common multiple of the denominators is 56 so:

(19/7) (8/8) - (7/8) (7/7)

(152-49) / 56

103/56 now we can change back into a mixed number ...

(56+47) / 56

1 47/56

19/7 - 7/8

19x8/7x8 - 7x7/8x7

152/56 - 49/56

103/56

1 47/56