Let's break this down. We're going to add 5035 and 1503 together.

Step 1: We'll start by adding the digits 5 & 3 in column 1 and get 8.

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

Step 3: We'll start by adding the digits 0 & 5 in column 3 and get 5.

Step 4: We'll start by adding the digits 5 & 1 in column 4 and get 6.

So, 5035 + 1503 = 6538.

