Correction :

18 + 22 = 40	44 - 23 = 21
6 + 12 = 18	38 - 21 = 17
44 : 4 = 11	39 - 15 = 24
5 : 1 = 5	27 - 20 = 7
15 + 23 = 38	28 - 8 = 20
19 + 6 = 25	6 + 18 = 24
29 - 20 = 9	21 + 24 = 45
29 - 11 = 18	18 - 3 = 15
9 × 1 = 9	14 - 11 = 3
17 - 5 = 12	21 + 13 = 34