Let's break this down. We're going to add 3036 and 4721 together.

Step 1: We'll start by adding the digits 6 & 1 in column 1 and get 7.

Step 2: We'll start by adding the digits 3 & 2 in column 2 and get 5.

Step 3: We'll start by adding the digits 0 & 7 in column 3 and get 7.

Step 4: We'll start by adding the digits 3 & 4 in column 4 and get 7.

So, 3036 + 4721 = 7757.

