7. 2+6 2+7 8-4 9-5 7-6+8 9-7+5 10-0 18+0

2 + 6 = 8

2 + 7 = 9

8 - 4 = 4

9 - 5 = 4

7 - 6 + 8 = 9

9 - 7 + 5 = 7

10 - 0 = 10

18 + 0 = 18