Correction :

26 - 15 = 11	2 + 23 = 25
41 - 21 = 20	10 - 6 = 4
19 - 0 = 19	32 - 15 = 17
14 + 0 = 14	21 - 5 = 16
8 + 11 = 19	20 + 20 = 40
17 - 15 = 2	28 : 7 = 4
5 + 14 = 19	10 + 2 = 12
3 + 23 = 26	23 + 5 = 28
21 + 10 = 31	26 - 7 = 19
16 + 24 = 40	27 - 10 = 17