Let's break this down. We're going to add 3931 and 3033 together.

Step 1: We'll start by adding the digits 1 & 3 in column 1 and get 4.

Step 2: We'll start by adding the digits 3 & 3 in column 2 and get 6.

Step 3: We'll start by adding the digits 9 & 0 in column 3 and get 9.

Step 4: We'll start by adding the digits 3 & 3 in column 4 and get 6.

So, 3931 + 3033 = 6964.

