Выполните действия 1) (12 3/8:2 1/16-5 5/21) * 7/8+3 2/15

(12 3/8:2 1/16-5 5/21) * 7/8+3 2/15 = (99/8 : 33/16 - 110/21) * 7/8 + 47/15 = (99/8*16/33-110/21) * 7/8+47/15 = (126/21-110/21) * 7/8 + 47/15=16/21*7/8+47/15=10/15+47/15=57/15 = 19/5 = 3 4/5

(12 3/8:2 1/16-5 5/21) * 7/8+3 2/15

пишу по действиям

12 3/8 = 99/8

2 1/16 = 33/16

5 5/21 = 110/21

3 2/15 = 47/15

12 3/8:2 1/16 = 99/8 : 33/16 = 99/8 * 16/33 = 99/33*16/8 = 3*2 = 6

6 - 110/21 = (126-110) / 21 = 16/21

16/21 * 7/8 = 16/8 * 7/21 = 2/3

2/3 + 47/15 = 10/15 + 47/15 = 57/15 = 19/5 = 3 4/5

ответ 3 4/5