Correction :

27 : 3 = 9	5 + 4 = 9
6 + 18 = 24	24 - 4 = 20
7 - 2 = 5	48 : 8 = 6
7 × 3 = 21	15 + 8 = 23
24 - 20 = 4	41 - 17 = 24
39 - 15 = 24	20 + 18 = 38
20 + 2 = 22	27 - 7 = 20
9 × 3 = 27	38 - 15 = 23
40 - 21 = 19	28 - 14 = 14
10 + 19 = 29	7 - 3 = 4