Пошаговое объяснение:
9/10 - (3/4 - 3/5) + 5/8 = 11/8
1) 3/4 - 3/5 = 15/20 - 12/20 = 3/20
2) 9/10 - 3/20 = 18/20 - 3/20 = 15/20 = 3/4
3) 3/4 + 5/8 = 6/8 + 5/8 = 11/8