Let's solve this addition problem. We have 7907 and 5210, and we need to add them together.

Step 1: We'll start by adding the digits 7 & 0 in column 1 and get 7.

Step 2: We'll start by adding the digits 0 & 1 in column 2 and get 1.

Step 3: We'll start by adding the digits 9 & 2 in column 3 and get 11.
We'll write down the last digit 1 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 7 & 5 in column 4 and get 13.
We'll write down the last digit 3 and carry the 1 to the next column.

So, 7907 + 5210 = 13117.

