Find Numbers Before and After 9999: Complete the Sequence

To find the numbers before and after 9999, we will follow these steps:

• Step 1: Identify the predecessor. The predecessor of 9999 is determined by subtracting 1 from 9999.
• Step 2: Identify the successor. The successor of 9999 is found by adding 1 to 9999.

Let's apply these steps:

Step 1: Calculate the predecessor of 9999.
The predecessor is $9999 - 1 = 9998$.

Step 2: Calculate the successor of 9999.
The successor is $9999 + 1 = 10000$.

Therefore, the numbers before and after 9999 are $9998$ and $10000$, respectively.

The correct choice among the options is option 2: $9998,10000$.