Пошаговое объяснение:
1) 100÷20 = 5
2) 7+5 = 12
3) 8÷3 = 2
4) 40 - 2 = 37
5) 5-12 = -7
6) -7+31 = 26
7) 26-37 = -11
= 37
= -11
