We have numbers 9666 and 9930. Let's start adding them 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 6 & 3 in column 2 and get 9.

Step 3: We'll start by adding the digits 6 & 9 in column 3 and get 15.
We'll write down the last digit 5 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 9 & 9 in column 4 and get 19.
We'll write down the last digit 9 and carry the 1 to the next column.

So, 9666 + 9930 = 19596.

