Correction :

10 + 18 = 28	6 + 13 = 19
3 + 7 = 10	10 × 6 = 60
42 - 20 = 22	45 : 5 = 9
90 : 9 = 10	90 : 10 = 9
23 + 7 = 30	1 × 4 = 4
32 - 9 = 23	8 : 4 = 2
3 × 11 = 33	38 - 23 = 15
25 - 9 = 16	24 + 2 = 26
4 + 9 = 13	3 × 6 = 18
36 - 22 = 14	23 - 7 = 16