Correction :

10 + 12 = 22	16 - 12 = 4
30 : 6 = 5	22 + 16 = 38
8 + 9 = 17	11 × 3 = 33
17 - 2 = 15	23 + 4 = 27
20 - 20 = 0	16 + 21 = 37
23 + 11 = 34	23 + 15 = 38
14 + 20 = 34	13 + 2 = 15
20 - 3 = 17	28 - 8 = 20
24 - 9 = 15	7 : 1 = 7
23 - 1 = 22	22 + 2 = 24