Complete the Number Sequence: Finding Missing Terms Around 4400

To solve this problem, let's methodically follow these steps:

• Step 1: Identify the predecessor of 4400.
  To find the predecessor, subtract 1 from 4400:
  $4400 - 1 = 4399$
• Step 2: Identify the successor of 4400.
  To find the successor, add 1 to 4400:
  $4400 + 1 = 4401$

Having followed these steps, we can conclude that the numbers we are looking for are $4399$ and $4401$.

Thus, the solution to the problem is $4399, 4401$.