Correction :

1 + 5 = 6	19 - 15 = 4
24 + 17 = 41	28 - 23 = 5
8 - 0 = 8	20 + 16 = 36
35 - 23 = 12	24 + 7 = 31
11 + 17 = 28	24 + 10 = 34
41 - 20 = 21	22 + 11 = 33
6 × 9 = 54	11 + 0 = 11
23 + 12 = 35	6 + 15 = 21
13 - 9 = 4	21 - 7 = 14
13 + 22 = 35	20 - 17 = 3