Correction :

28 - 11 = 17	32 - 23 = 9
47 - 24 = 23	3 + 15 = 18
2 + 12 = 14	4 × 8 = 32
12 - 9 = 3	38 - 14 = 24
29 - 12 = 17	32 - 24 = 8
24 - 8 = 16	45 - 22 = 23
2 + 9 = 11	33 - 21 = 12
9 + 24 = 33	12 : 4 = 3
63 : 9 = 7	2 + 23 = 25
4 + 18 = 22	8 × 4 = 32