Alright, let's solve this problem step by step. We have 117 and 868 and we're adding them together.

Step 1: We'll start by adding the digits 7 & 8 in column 1 and get 15.
We'll write down the last digit 5 and carry the 1 to the next column.

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

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

So, 117 + 868 = 985.

