Let's break this down. We're going to add 3270 and 520 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 7 & 2 in column 2 and get 9.

Step 3: We'll start by adding the digits 2 & 5 in column 3 and get 7.

Step 4: We'll start by adding the digits 3 & 0 in column 4 and get 3.

So, 3270 + 520 = 3790.

