7.
12 - 8 + 6 = 4 + 6 = 10
11 - 7 + 8 = 4 + 8 = 12
12 - 5 + 8 = 7 + 8 = 15
30 - (20 - 6) = 30 - 14 = 16
40 - (30 - 6) = 40 - 24 = 16
50 - (40 - 6) = 50 - 34 = 16
56 - 7 = 49
34 - 6 = 28
63 + 7 = 70
Ответ: