Here the first 2 column have numbers above 6 and the the third column indicates the difference between the sum of numbers in the first 2 column and (6×2). For instance

The row

8 8 4

Comes to being because (8+8)-(2×6) = 4

Going by this logic for the row

10 10 ?

It should be (10+10)-(2×6)= 8