Correction :

15 - 4 = 11	23 - 4 = 19
22 - 15 = 7	26 - 7 = 19
10 + 15 = 25	13 + 11 = 24
20 : 2 = 10	6 + 24 = 30
7 + 16 = 23	14 - 10 = 4
32 - 18 = 14	23 - 0 = 23
20 + 9 = 29	42 - 24 = 18
9 × 10 = 90	5 + 22 = 27
1 × 9 = 9	19 + 14 = 33
12 - 3 = 9	7 × 8 = 56