Answer:
The trick to this problem is that first you have to subtract the digits and then add them. For example:
6 and 4, if we subtract them, we get 2 and if we add them, we get 10, therefore the answer is 210.
9 and 2, if we subtract them, we get 7 and if we add them, we get 11, therefore the answer is 711.
This works for the rest of the numbers as well and we can use it for the unknown problem
8 - 3 = 5
8 + 3 = 11
Therefore, the answer is 511
