Correction :

27 - 4 = 23	3 + 7 = 10
6 + 3 = 9	19 + 18 = 37
18 - 17 = 1	34 - 11 = 23
35 - 17 = 18	24 - 1 = 23
20 + 0 = 20	5 + 20 = 25
29 - 6 = 23	9 + 11 = 20
77 : 7 = 11	18 - 4 = 14
10 × 5 = 50	14 + 14 = 28
15 - 5 = 10	43 - 22 = 21
9 + 12 = 21	23 - 16 = 7