Let's break this down. We're going to add 3340 and 4031 together.

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

Step 2: We'll start by adding the digits 4 & 3 in column 2 and get 7.

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

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

So, 3340 + 4031 = 7371.

