Not to worry, we've got 406 and 9002. Let's get to adding them!

Step 1: We'll start by adding the digits 6 & 2 in column 1 and get 8.

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 & 0 in column 3 and get 4.

Step 4: We'll start by adding the digits 0 & 9 in column 4 and get 9.

So, 406 + 9002 = 9408.

