Correction :

31 - 17 = 14	24 + 0 = 24
16 - 4 = 12	21 - 8 = 13
18 + 18 = 36	3 + 20 = 23
46 - 23 = 23	32 - 13 = 19
39 - 15 = 24	36 - 18 = 18
10 + 0 = 10	34 - 14 = 20
24 + 1 = 25	8 + 3 = 11
18 - 8 = 10	20 - 17 = 3
18 - 15 = 3	10 × 9 = 90
16 - 1 = 15	3 : 1 = 3