Correction :

15 + 16 = 31	20 + 13 = 33
22 - 7 = 15	3 × 7 = 21
4 - 2 = 2	21 + 6 = 27
8 + 8 = 16	24 - 13 = 11
9 : 3 = 3	24 + 3 = 27
25 - 24 = 1	21 : 7 = 3
16 - 10 = 6	21 + 11 = 32
30 : 10 = 3	23 + 6 = 29
22 + 10 = 32	14 - 0 = 14
35 - 11 = 24	17 + 14 = 31