Correction :

19 + 6 = 25	99 : 11 = 9
42 - 24 = 18	11 + 23 = 34
28 - 23 = 5	60 : 6 = 10
77 : 11 = 7	12 + 13 = 25
16 + 17 = 33	28 - 16 = 12
30 : 10 = 3	0 + 19 = 19
20 + 17 = 37	21 - 9 = 12
20 + 6 = 26	13 - 3 = 10
2 : 2 = 1	31 - 18 = 13
19 + 9 = 28	28 : 7 = 4