Let's get this math done. We have 816 and 6680 and we're going to add them all together.

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

Step 2: We'll start by adding the digits 1 & 8 in column 2 and get 9.

Step 3: We'll start by adding the digits 8 & 6 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 & 6 in column 4 and get 7.

So, 816 + 6680 = 7496.

