Let's break this down. We're going to add 1406 and 7400 together.

Step 1: We'll start by adding the digits 6 & 0 in column 1 and get 6.

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

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 1 & 7 in column 4 and get 8.

So, 1406 + 7400 = 8806.

