No problem, let's work through this together. We're starting with 208 and 215 and adding them all up.

Step 1: We'll start by adding the digits 8 & 5 in column 1 and get 13.
We'll write down the last digit 3 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 0 & 1 in column 2 and get 2.

Step 3: We'll start by adding the digits 2 & 2 in column 3 and get 4.

So, 208 + 215 = 423.

