Okay, we are tasked with adding 666 and 224. Let's begin!

Step 1: We'll start by adding the digits 6 & 4 in column 1 and get 10.
We'll write down the last digit 0 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 6 & 2 in column 2 and get 9.

Step 3: We'll start by adding the digits 6 & 2 in column 3 and get 8.

So, 666 + 224 = 890.

