We have numbers 665 and 2805. Let's start adding them together.

Step 1: We'll start by adding the digits 5 & 5 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 & 0 in column 2 and get 7.

Step 3: We'll start by adding the digits 6 & 8 in column 3 and get 14.
We'll write down the last digit 4 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 0 & 2 in column 4 and get 3.

So, 665 + 2805 = 3470.

