We are presented with 9809 and 1806. Let's work out the sum.

Step 1: We'll start by adding the digits 9 & 6 in column 1 and get 15.
We'll write down the last digit 5 and carry the 1 to the next column.

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

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 9 & 1 in column 4 and get 11.
We'll write down the last digit 1 and carry the 1 to the next column.

So, 9809 + 1806 = 11615.

