Correction :

5 + 22 = 27	17 - 0 = 17
24 + 4 = 28	13 - 3 = 10
19 - 2 = 17	7 + 24 = 31
22 - 15 = 7	3 × 1 = 3
7 + 0 = 7	8 + 17 = 25
23 - 20 = 3	50 : 10 = 5
18 + 8 = 26	4 - 3 = 1
18 - 16 = 2	5 - 0 = 5
33 - 11 = 22	2 + 17 = 19
38 - 17 = 21	11 : 11 = 1