Correction :

38 - 22 = 16	21 + 22 = 43
3 + 4 = 7	31 - 15 = 16
15 + 23 = 38	16 - 10 = 6
30 - 6 = 24	23 - 16 = 7
16 - 16 = 0	23 - 20 = 3
24 + 22 = 46	7 × 3 = 21
8 + 6 = 14	11 - 4 = 7
5 + 22 = 27	4 + 19 = 23
14 - 3 = 11	42 - 21 = 21
35 - 24 = 11	35 : 7 = 5