7: (5/8+5/6)+(три целых одна девятая-1/3)•(3/10)в квадрате

7:(5/8+5/6)+(3 1/9-1/3)•(3/10)^2 = 5 1/20

5/8+5/6 = 30/48 + 40/48 = 70/48 = 35/24 = 1 11/24
7:35/24 = 7*24/35 = 24/5 = 4 4/5

3 1/9-1/3 = 3 1/9 - 3/9 = 2 7/9
(3/10)^2 = 3/10*3/10 = 9/100
2 7/9*9/100 = 25/9*9/100=1/4

4 4/5 + 1/4 = 4 16/20 + 5/20 = 4 21/20 = 5 1/20