To create a whole number using 3.1, 3.7, and 2.5, where each number can only be used once, we need to find a combination of operations (addition, subtraction, multiplication, or division) that results in an integer.

Let's explore the operations:

$(3.1 + 3.7) \times 2.5 = 6.8 \times 2.5 = 17$

This combination gives us 17, which is a whole number.

This is one possible solution where each number is used only once.

Would you like more details or have any other questions?

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Here are 8 related questions to explore:

1. Can you find another combination that results in a different whole number?
2. What is the result if you subtract 2.5 from the sum of 3.1 and 3.7?
3. Can these numbers create a whole number if you use division instead of multiplication?
4. What happens if you multiply 3.1 by 3.7 and then add 2.5?
5. Can adding all three numbers together ever result in a whole number?
6. How can you create the largest possible whole number using these three numbers?
7. What happens if you swap the order of operations? Does it change the result?
8. Can you use just two of these numbers to create a whole number?

Tip: Always pay attention to the order of operations (PEMDAS) when combining numbers, as it can significantly impact the outcome.