Let's break this down. We're going to add 6470 and 6166 together.

Step 1: We'll start by adding the digits 0 & 6 in column 1 and get 6.

Step 2: We'll start by adding the digits 7 & 6 in column 2 and get 13.
We'll write down the last digit 3 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 4 & 1 in column 3 and get 6.

Step 4: We'll start by adding the digits 6 & 6 in column 4 and get 12.
We'll write down the last digit 2 and carry the 1 to the next column.

So, 6470 + 6166 = 12636.

