We have numbers 1180 and 8817. Let's start adding them 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 8 & 1 in column 2 and get 9.

Step 3: We'll start by adding the digits 1 & 8 in column 3 and get 9.

Step 4: We'll start by adding the digits 1 & 8 in column 4 and get 9.

So, 1180 + 8817 = 9997.

