Correction :

15 + 15 = 30	9 × 8 = 72
19 - 13 = 6	23 - 21 = 2
29 - 11 = 18	6 + 5 = 11
33 - 23 = 10	21 - 4 = 17
27 - 15 = 12	25 - 21 = 4
7 × 3 = 21	38 - 24 = 14
30 : 6 = 5	5 - 0 = 5
11 × 2 = 22	10 - 4 = 6
20 + 22 = 42	8 × 4 = 32
23 + 2 = 25	24 - 13 = 11