Correction :

29 - 12 = 17	23 - 19 = 4
23 - 4 = 19	36 - 22 = 14
8 - 2 = 6	30 - 15 = 15
23 - 21 = 2	22 - 4 = 18
14 - 2 = 12	7 + 6 = 13
28 - 9 = 19	9 + 18 = 27
20 : 4 = 5	2 + 19 = 21
27 - 24 = 3	11 + 13 = 24
30 - 17 = 13	1 + 10 = 11
6 + 2 = 8	3 + 11 = 14