Ответ:

1) 4

2) 43/6

Пошаговое объяснение:

1) 4 3/8 - (3 5/7 - 1 5/7) + 1 5/8 = 35/8 - (26/7 - 12/7) + 13/8 = 35/8 - 2 + 13/8 = 4

2) 12 7/12 - 4 5/12 - (20 3/4 - 19 3/4) = 151/12 - 53/12 - (83/4 - 79/4) = 151/12 - 53/12 - 1 = 43/6

4 3/8 - (3 5/7 - 1 5/7) + 1 5/8=4

12 7/12 - 4 5/12 - (20 3/4 - 19 3/4)=7 1/6