Let's solve this addition problem. We have 2518 and 5129, and we need to add them together.

Step 1: We'll start by adding the digits 8 & 9 in column 1 and get 17.
We'll write down the last digit 7 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 1 & 2 in column 2 and get 4.

Step 3: We'll start by adding the digits 5 & 1 in column 3 and get 6.

Step 4: We'll start by adding the digits 2 & 5 in column 4 and get 7.

So, 2518 + 5129 = 7647.

