Correction :

2 + 0 = 2	30 - 16 = 14
5 × 10 = 50	12 - 9 = 3
5 + 3 = 8	21 - 18 = 3
2 + 16 = 18	23 + 22 = 45
28 - 7 = 21	22 + 20 = 42
9 - 5 = 4	20 - 20 = 0
2 + 20 = 22	27 - 18 = 9
25 - 21 = 4	23 + 5 = 28
110 : 10 = 11	66 : 11 = 6
25 - 4 = 21	1 + 20 = 21