Correction :

12 + 8 = 20	11 - 6 = 5
5 + 10 = 15	20 + 3 = 23
35 - 16 = 19	1 × 6 = 6
23 - 5 = 18	3 × 6 = 18
39 - 23 = 16	19 + 1 = 20
19 + 22 = 41	22 - 7 = 15
10 : 1 = 10	23 + 4 = 27
24 - 24 = 0	16 + 6 = 22
15 - 8 = 7	17 + 3 = 20
22 - 2 = 20	4 + 0 = 4