Correction :

3 + 24 = 27	9 + 7 = 16
15 - 8 = 7	37 - 22 = 15
15 + 22 = 37	4 + 15 = 19
20 + 10 = 30	23 - 13 = 10
43 - 24 = 19	26 - 12 = 14
7 : 7 = 1	26 - 17 = 9
9 - 9 = 0	30 - 24 = 6
8 - 4 = 4	25 - 8 = 17
5 × 11 = 55	26 - 22 = 4
22 - 21 = 1	5 × 11 = 55