Answer:
99,999.
Explanation:
We are asked to write a 5-digit number that when rounded to the nearest thousand and hundred will have a result that is the same.
We know that when the next digit to rounded digit is 0, 1, 2, 3, 4; then we keep the same digit.
When the next digit to rounded digit is 5 or more than 5; then we round up our answer by one digit.
In our five-digit number each digit would be same.
Let use take 6 as:

To nearest hundred:

To nearest thousand:

Let us take 9:

To nearest hundred:

To nearest thousand:

Therefore, our required digit is 99,999.