Correction :

19 + 7 = 26	32 - 13 = 19
10 - 10 = 0	13 + 0 = 13
39 - 24 = 15	4 + 2 = 6
21 + 20 = 41	9 - 5 = 4
20 - 5 = 15	40 - 24 = 16
19 + 1 = 20	25 - 12 = 13
9 × 3 = 27	21 + 7 = 28
2 - 0 = 2	2 + 12 = 14
22 + 8 = 30	42 - 22 = 20
8 × 7 = 56	24 - 16 = 8