Correction :

11 + 0 = 11	7 + 0 = 7
11 + 8 = 19	11 : 1 = 11
27 - 13 = 14	31 - 24 = 7
0 - 0 = 0	5 + 1 = 6
8 - 1 = 7	12 - 5 = 7
21 + 14 = 35	17 - 5 = 12
26 - 16 = 10	2 + 12 = 14
33 - 21 = 12	19 + 1 = 20
44 - 20 = 24	99 : 11 = 9
12 + 19 = 31	10 + 21 = 31