Alright, let's solve this problem step by step. We have 507 and 181 and we're adding them together.

Step 1: We'll start by adding the digits 7 & 1 in column 1 and get 8.

Step 2: We'll start by adding the digits 0 & 8 in column 2 and get 8.

Step 3: We'll start by adding the digits 5 & 1 in column 3 and get 6.

So, 507 + 181 = 688.

