a. Smallest number:

To form the smallest number, we arrange the digits in ascending order. The given digits are 2, 7, 5, 9, and 8.

• Smallest number = 25789

b. Largest number:

To form the largest number, we arrange the digits in descending order.

• Largest number = 98752

c. Four different 5-digit numbers:

Here are four different 5-digit numbers that can be formed using the given digits (2, 7, 5, 9, and 8) without repeating any digits:

1. 79528
2. 85927
3. 27598
4. 52897

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Would you like details on how these combinations were chosen?

Related questions:

1. What happens if digits can be repeated? How does that affect the smallest or largest numbers?
2. How would you form numbers using only a subset of these digits?
3. What would the largest possible sum be if you add up four such 5-digit numbers?
4. How many distinct 5-digit numbers can be formed using the digits 2, 7, 5, 9, and 8?
5. What would change if a digit were excluded from the set?

Tip:

To form the smallest or largest number, always arrange the digits in ascending or descending order, respectively.