Correction :

2 + 7 = 9	37 - 14 = 23
8 + 21 = 29	16 + 22 = 38
7 + 19 = 26	38 - 19 = 19
13 - 5 = 8	26 - 22 = 4
25 - 5 = 20	19 - 7 = 12
8 - 7 = 1	16 - 14 = 2
8 - 1 = 7	13 + 3 = 16
24 + 11 = 35	28 - 24 = 4
1 : 1 = 1	13 + 16 = 29
15 - 12 = 3	14 + 8 = 22