Let's break this down. We're going to add 320 and 4200 together.

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

Step 2: We'll start by adding the digits 2 & 0 in column 2 and get 2.

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

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

So, 320 + 4200 = 4520.

