Correction :

15 + 3 = 18	4 + 21 = 25
88 : 11 = 8	39 - 21 = 18
38 - 16 = 22	23 - 20 = 3
16 - 5 = 11	13 + 4 = 17
13 - 1 = 12	11 + 19 = 30
20 - 6 = 14	26 - 19 = 7
2 × 6 = 12	15 - 1 = 14
3 + 21 = 24	10 - 7 = 3
7 + 5 = 12	13 - 10 = 3
10 × 11 = 110	11 + 10 = 21