We have numbers 500 and 105. Let's start adding them together.

Step 1: We'll start by adding the digits 0 & 5 in column 1 and get 5.

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 5 & 1 in column 3 and get 6.

So, 500 + 105 = 605.

