Correction :

27 - 12 = 15	13 - 13 = 0
1 + 22 = 23	17 - 9 = 8
32 - 24 = 8	32 - 18 = 14
27 - 12 = 15	5 × 5 = 25
12 + 24 = 36	17 - 17 = 0
11 - 0 = 11	1 + 10 = 11
30 - 15 = 15	4 + 20 = 24
4 + 23 = 27	4 + 13 = 17
33 - 16 = 17	19 + 13 = 32
16 + 21 = 37	32 - 18 = 14