Not to worry, we've got 661 and 1002. Let's get to adding them!

Step 1: We'll start by adding the digits 1 & 2 in column 1 and get 3.

Step 2: We'll start by adding the digits 6 & 0 in column 2 and get 6.

Step 3: We'll start by adding the digits 6 & 0 in column 3 and get 6.

Step 4: We'll start by adding the digits 0 & 1 in column 4 and get 1.

So, 661 + 1002 = 1663.

