Here we go! We're going to add 817 and 2015 together.

Step 1: We'll start by adding the digits 7 & 5 in column 1 and get 12.
We'll write down the last digit 2 and carry the 1 to the next column.

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

Step 3: We'll start by adding the digits 8 & 0 in column 3 and get 8.

Step 4: We'll start by adding the digits 0 & 2 in column 4 and get 2.

So, 817 + 2015 = 2832.

