Correction :

10 + 15 = 25	36 - 20 = 16
31 - 23 = 8	23 + 22 = 45
5 + 21 = 26	24 : 6 = 4
20 : 2 = 10	8 - 4 = 4
3 + 14 = 17	7 - 6 = 1
29 - 6 = 23	42 - 24 = 18
2 + 17 = 19	30 - 18 = 12
4 + 14 = 18	0 + 4 = 4
13 + 19 = 32	9 × 3 = 27
11 × 7 = 77	8 + 12 = 20