Correction :

13 - 8 = 5	11 × 10 = 110
5 × 9 = 45	21 - 9 = 12
5 × 5 = 25	29 - 7 = 22
13 + 0 = 13	4 × 4 = 16
1 + 11 = 12	9 - 8 = 1
10 - 6 = 4	11 × 4 = 44
26 - 17 = 9	21 + 16 = 37
21 + 12 = 33	11 × 9 = 99
24 + 2 = 26	21 + 7 = 28
21 + 8 = 29	1 : 1 = 1