Ответ:

2/3

Пошаговое объяснение:

1) 8 7/15 - 3 3/4 = 8 28/60 - 3 45/60 = 7 88/60 - 3 45/60 = 4 43/60

2) 4 43/60 + 4 2/5 = 4 43/60 + 4 24/60 = 8 67/60 = 9 7/60

3) 9 7/60 - 8 7/60 = 1

4) 4 1/4 - 2 3/4 = 3 5/4 - 2 3/4 = 1 2/4 = 1 1/2

5) 1 : 1 1/2 = 1 : 3/2 = 1 * 2/3 = 2/3