Correction :

34 - 19 = 15	40 - 20 = 20
18 - 9 = 9	8 × 6 = 48
29 - 11 = 18	19 + 7 = 26
55 : 11 = 5	5 : 5 = 1
28 - 11 = 17	6 × 4 = 24
16 + 20 = 36	21 + 21 = 42
37 - 15 = 22	5 + 3 = 8
29 - 6 = 23	44 - 20 = 24
28 - 16 = 12	18 + 21 = 39
2 × 5 = 10	10 + 15 = 25