Let's break this down. We're going to add 2421 and 3342 together.

Step 1: We'll start by adding the digits 1 & 2 in column 1 and get 3.

Step 2: We'll start by adding the digits 2 & 4 in column 2 and get 6.

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

Step 4: We'll start by adding the digits 2 & 3 in column 4 and get 5.

So, 2421 + 3342 = 5763.

