Let's break this down. We're going to add 400 and 8257 together.

Step 1: We'll start by adding the digits 0 & 7 in column 1 and get 7.

Step 2: We'll start by adding the digits 0 & 5 in column 2 and get 5.

Step 3: We'll start by adding the digits 4 & 2 in column 3 and get 6.

Step 4: We'll start by adding the digits 0 & 8 in column 4 and get 8.

So, 400 + 8257 = 8657.

