Let's solve this addition problem. We have 252 and 1015, and we need to add them together.

Step 1: We'll start by adding the digits 2 & 5 in column 1 and get 7.

Step 2: We'll start by adding the digits 5 & 1 in column 2 and get 6.

Step 3: We'll start by adding the digits 2 & 0 in column 3 and get 2.

Step 4: We'll start by adding the digits 0 & 1 in column 4 and get 1.

So, 252 + 1015 = 1267.

