Not to worry, we've got 404 and 403. Let's get to adding them!

Step 1: We'll start by adding the digits 4 & 3 in column 1 and get 7.

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.

So, 404 + 403 = 807.

