Correction :

25 - 12 = 13	31 - 22 = 9
8 - 0 = 8	12 + 1 = 13
5 + 10 = 15	41 - 22 = 19
8 + 4 = 12	23 + 3 = 26
31 - 13 = 18	14 + 22 = 36
25 - 18 = 7	27 - 22 = 5
12 + 21 = 33	31 - 14 = 17
11 - 2 = 9	24 - 12 = 12
20 - 14 = 6	99 : 11 = 9
23 + 16 = 39	17 + 0 = 17