Okay, we are given 9948 and 6651. Let's add them up step by step.

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

Step 2: We'll start by adding the digits 4 & 5 in column 2 and get 9.

Step 3: We'll start by adding the digits 9 & 6 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 & 6 in column 4 and get 16.
We'll write down the last digit 6 and carry the 1 to the next column.

So, 9948 + 6651 = 16599.

