Correction :

8 + 4 = 12	12 - 3 = 9
15 - 4 = 11	18 + 16 = 34
9 + 7 = 16	25 - 23 = 2
16 - 16 = 0	0 + 23 = 23
15 + 16 = 31	11 + 11 = 22
25 - 5 = 20	23 + 22 = 45
13 + 15 = 28	10 - 6 = 4
31 - 8 = 23	23 - 5 = 18
32 - 18 = 14	11 + 9 = 20
21 - 17 = 4	5 + 17 = 22