Correction :

4 + 1 = 5	11 + 11 = 22
41 - 17 = 24	28 - 15 = 13
1 + 19 = 20	24 - 16 = 8
24 - 21 = 3	0 + 13 = 13
9 + 7 = 16	13 + 6 = 19
66 : 6 = 11	30 : 5 = 6
21 + 23 = 44	29 - 15 = 14
24 - 8 = 16	16 - 15 = 1
7 + 17 = 24	1 + 13 = 14
23 + 2 = 25	8 - 1 = 7