Correction :

13 - 9 = 4	24 + 0 = 24
20 + 17 = 37	36 : 4 = 9
17 + 19 = 36	32 - 15 = 17
25 - 18 = 7	17 + 2 = 19
60 : 6 = 10	28 - 15 = 13
4 + 9 = 13	18 + 3 = 21
3 + 15 = 18	36 - 14 = 22
15 + 20 = 35	30 : 6 = 5
2 + 18 = 20	7 × 4 = 28
31 - 17 = 14	20 - 13 = 7