Correction :

9 + 1 = 10	17 + 21 = 38
15 + 12 = 27	10 - 6 = 4
8 - 4 = 4	15 + 19 = 34
29 - 8 = 21	37 - 21 = 16
25 - 8 = 17	2 : 2 = 1
22 + 9 = 31	6 + 20 = 26
39 - 21 = 18	23 - 13 = 10
17 + 23 = 40	14 + 1 = 15
22 + 15 = 37	11 × 5 = 55
20 + 1 = 21	1 + 14 = 15