Mystery Number Riddles - read all the clues, find the mystery number

Sep 30, 2026

Mystery Number Riddles provides 20 number clues that guide a solver to identify a “mystery number” between 1 and 100. Each clue states precise properties such as composite or prime, divisibility by specific factors, parity (even or odd), and inclusive number ranges. An answer key lists the resolved numbers for each clue, enabling self-check and targeted practice in number properties and reasoning.

LanguageEnglish

CategoryExam

FormatPDF

Pages3

Reading Time8 min

AccessFree to download

Clues

Clue 1-10

Clue 11-20

Answers

Mystery Number Riddles Name: Read all the clues. Use them to figure out the mystery number between 1 and 100. 1) I am a composite number. I am a multiple of 4. I am between 15 and 25. I am a multiple of 5. 2) I am a composite number. I am a multiple of 8. I am between 75 and 85. I am a multiple of 5. 3) I am a composite number. I am between 85 and 90. I am a multiple of 3. I am odd. 4) I am a prime number. I am between 85 and 90. 5) I am less than 10. I am a composite number. I am a multiple of 4. I am greater than 5. 6) I am a composite number. I am a multiple of 9. I am between 85 and 95. I am even. 7) I am between 30 and 35. I am a composite number. I am a multiple of 3. I am odd. 8) I am a composite number. I am between 80 and 90. I am a multiple of 7. I am even. 9) I am less than 10. I am a composite number. I am a multiple of 3. I am even. 10) I am a composite number. I am between 65 and 70. I am a multiple of 4. 11) I am a composite number. I am a multiple of 6. I am between 55 and 65. I am a multiple of 5. 12) I am a composite number. I am a multiple of 5. I am between 30 and 40. I am odd. 13) I am less than 5. I am a prime number. I am even. 14) I am a composite number. I am a multiple of 8. I am between 30 and 40. 15) I am a composite number. I am between 70 and 80. I am a multiple of 7. I am odd. 16) I am a prime number. I am between 10 and 15. I am less than 12. 17) I am a prime number. I am between 65 and 70. 18) I am a composite number. I am a multiple of 7. I am between 50 and 60. 19) I am a prime number. I am between 60 and 65. 20) I am between 40 and 50. I am a composite number. I am a multiple of 9. Answers 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. Math [www.CommonCoreSheets.com](www.CommonCoreSheets.com) 1-10 11-20 95 45 90 40 85 35 80 30 75 25 70 20 65 15 60 10 55 5 50 0 Mystery Number Riddles Name: Answer Key | Read all the clues. Use them to figure out the mystery number between 1 and 100.
1) I am a composite number. I am a multiple of 4. I am between 15 and 25. I am a multiple of 5. | | Answers
1. 20 | | --- | --- | --- | | 2) | I am a composite number. I am a multiple of 8. I am between 75 and 85. I am a multiple of 5. | 2. 80 | | 3) | I am a composite number. I am between 85 and 90. I am a multiple of 3. I am odd. | 3. 87 | | 4) | I am a prime number. I am between 85 and 90. | 4. 89 | | 5) | I am less than 10. I am a composite number. I am a multiple of 4. I am greater than 5. | 5. 8 | | 6) | I am a composite number. I am a multiple of 9. I am between 85 and 95. I am even. | 6. 90 | | 7) | I am between 30 and 35. I am a composite number. I am a multiple of 3. I am odd. | 7. 33 | | 8) | I am a composite number. I am between 80 and 90. I am a multiple of 7. I am even. | 8. 84 | | 9) | I am less than 10. I am a composite number. I am a multiple of 3. I am even. | 9. 6 | | 10) | I am a composite number. I am between 65 and 70. I am a multiple of 4. | | | 11) | I am a composite number. I am a multiple of 6. I am between 55 and 65. I am a multiple of 5. | 10. 68 11. 60 | | 12) | I am a composite number. I am a multiple of 5. I am between 30 and 40. I am odd. | | | 13) | I am less than 5. I am a prime number. I am even. | 12. 35 | | 14) | I am a composite number. I am a multiple of 8. I am between 30 and 40. | 13. 2 | | 15) | I am a composite number. I am between 70 and 80. I am a multiple of 7. I am odd. | 14. 32 | | 16) | I am a prime number. I am between 10 and 15. I am less than 12. | 15. 77 | | 17) | I am a prime number. I am between 65 and 70. | 16. 11 | | 18) | I am a composite number. I am a multiple of 7. I am between 50 and 60. | 17. 67 | | 19) | I am a prime number. I am between 60 and 65. | 18. 56 | | 20) | I am between 40 and 50. I am a composite number. I am a multiple of 9. | 19. 61 20. 45 | Math S

FAQs

How do you solve each Mystery Number Riddle?

Read all the conditions in a clue—prime/composite, divisibility, parity, and the stated range—then determine the number between 1 and 100 that satisfies every condition.

What does the answer key contain?

The answer key lists the solved mystery numbers for clues 1 through 20, so you can verify your results.

What kinds of math skills do these riddles practice?

They practice recognizing prime vs. composite numbers, applying divisibility rules, using even/odd properties, and reasoning with numeric ranges.

Sep 30, 2026

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