Correction :

6 + 15 = 21	8 + 3 = 11
20 - 1 = 19	28 - 18 = 10
45 - 22 = 23	22 - 5 = 17
19 - 13 = 6	18 + 18 = 36
21 : 3 = 7	20 - 14 = 6
10 × 10 = 100	29 - 18 = 11
23 + 6 = 29	32 : 4 = 8
15 + 9 = 24	19 - 1 = 18
1 + 17 = 18	4 × 2 = 8
23 - 9 = 14	18 + 7 = 25