Okay, we are tasked with adding 6820 and 6800. Let's begin!

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

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

Step 3: We'll start by adding the digits 8 & 8 in column 3 and get 16.
We'll write down the last digit 6 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 6 & 6 in column 4 and get 13.
We'll write down the last digit 3 and carry the 1 to the next column.

So, 6820 + 6800 = 13620.

