(5 5/6:4+7:5 1/11):7/9-4/9*3/8

(5 5/6 : 4 + 7 : 5 1/11) : 7/9 - 4/9 · 3/8 = 3 10/21

1) 5 5/6 : 4 = 35/6 · 1/4 = 35/24 = 1 11/24

2) 7 : 5 1/11 = 7 : 56/11 = 7/1 · 11/56 = (1·11)/(1·8) = 11/8 = 1 3/8

3) 1 11/24 + 1 3/8 = 1 11/24 + 1 9/24 = 2 20/24 = 2 5/6

4) 2 5/6 : 7/9 = 17/6 · 9/7 = (17·3)/(2·7) = 51/14 = 3 9/14

5) 4/9 · 3/8 = (1·1)/(3·2) = 1/6

6) 3 9/14 - 1/6 = 3 27/42 - 7/42 = 3 20/42 = 3 10/21

ответ: 3 целых 10/21.