По действиям : (7 целых 1/2*2 целых 2/3-12 целых 1/4:7/9) : 6+3 целых 1/8 + 5 целых 2/7=

5 целых 1/3 : 6 целых 2/5 + (12 целых: 3 целых 3/5 - 2/3) * 2/3 + 7 целых 2/5 =

1.

(7 1/2 * 2 2/3 - 12 1/4 : 7/9) : 6 + 3 1/8 + 5 2/7 = 9 5/42,

1) 7 1/2 * 2 2/3 = 15/2 * 8/3 = 20,

2) 12 1/4 : 7/9 = 49/4 * 9/7 = 63/4 = 15 3/4 (или 15,75),

3) 20 - 15 3/4 = 4 1/4,

4) 4 1/4 : 6 = 17/4 * 1/6 = 17/24,

5) 17/24 + 3 1/8 = 17/24 + 25/8 = 17/24 + 75/24 = 92/24 = 23/6 = 3 5/6,

6) 3 5/6 + 5 2/7 = (3 + 5) + (5/6 + 2/7) = 8 + (35/42 + 12/42) = 8 + 47/42 = 8 + 1 5/42 = 9 5/42.