Let's solve this addition problem. We have 1680 and 9120, and we need to add them together.

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 8 & 2 in column 2 and get 10.
We'll write down the last digit 0 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 6 & 1 in column 3 and get 8.

Step 4: We'll start by adding the digits 1 & 9 in column 4 and get 10.
We'll write down the last digit 0 and carry the 1 to the next column.

So, 1680 + 9120 = 10800.

