We have numbers 806 and 4255. Let's start adding them together.

Step 1: We'll start by adding the digits 6 & 5 in column 1 and get 11.
We'll write down the last digit 1 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 0 & 5 in column 2 and get 6.

Step 3: We'll start by adding the digits 8 & 2 in column 3 and get 10.
We'll write down the last digit 0 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 0 & 4 in column 4 and get 5.

So, 806 + 4255 = 5061.

