Correction :

25 - 10 = 15	30 - 23 = 7
5 : 5 = 1	39 - 19 = 20
19 + 13 = 32	23 - 5 = 18
14 + 21 = 35	18 - 6 = 12
10 + 5 = 15	9 + 22 = 31
2 + 14 = 16	23 + 16 = 39
16 + 5 = 21	24 - 10 = 14
17 - 15 = 2	2 × 2 = 4
55 : 11 = 5	4 - 0 = 4
13 - 1 = 12	41 - 24 = 17