Let's break this down. We're going to add 5423 and 2112 together.

Step 1: We'll start by adding the digits 3 & 2 in column 1 and get 5.

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

Step 3: We'll start by adding the digits 4 & 1 in column 3 and get 5.

Step 4: We'll start by adding the digits 5 & 2 in column 4 and get 7.

So, 5423 + 2112 = 7535.

