Correction :

34 - 19 = 15	1 × 7 = 7
4 + 14 = 18	16 - 16 = 0
10 × 8 = 80	18 - 8 = 10
15 - 8 = 7	19 - 17 = 2
2 + 16 = 18	24 - 1 = 23
81 : 9 = 9	18 : 6 = 3
13 + 3 = 16	10 + 24 = 34
11 × 4 = 44	32 - 15 = 17
21 - 21 = 0	38 - 24 = 14
40 - 16 = 24	15 + 15 = 30