Let's break this down. We're going to add 5443 and 420 together.

Step 1: We'll start by adding the digits 3 & 0 in column 1 and get 3.

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

Step 3: We'll start by adding the digits 4 & 4 in column 3 and get 8.

Step 4: We'll start by adding the digits 5 & 0 in column 4 and get 5.

So, 5443 + 420 = 5863.

