SOF International Mathematics Olympiad (IMO)
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IMO Level 1
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2025
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Sample
Which type of decimal expansion does the rational number 9/2 have?
Explanation
Explanation
A fraction has a terminating decimal expansion exactly when the denominator (in lowest terms) has no prime factors other than 2 and 5. Here 2 = 2, so 9/2 = 4.5 terminates.
PRO TIP
Re-check your working by substituting the answer back into the original question.