Correction :

11 + 0 = 11	13 - 13 = 0
21 : 3 = 7	17 + 17 = 34
36 : 9 = 4	5 + 23 = 28
30 - 18 = 12	1 × 3 = 3
36 - 12 = 24	2 + 14 = 16
40 : 5 = 8	29 - 24 = 5
35 - 16 = 19	8 - 7 = 1
20 - 0 = 20	17 + 11 = 28
5 + 18 = 23	17 + 9 = 26
10 + 18 = 28	15 + 11 = 26