Let's break this down. We're going to add 2124 and 7634 together.

Step 1: We'll start by adding the digits 4 & 4 in column 1 and get 8.

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

Step 3: We'll start by adding the digits 1 & 6 in column 3 and get 7.

Step 4: We'll start by adding the digits 2 & 7 in column 4 and get 9.

So, 2124 + 7634 = 9758.

