1. I am the largest prime number which is less than 36.
    Who am I?     31
  2. I am the smallest even number which when rounded to the nearest ten is 90.
    Who am I?     86
  3. I am the least common multiple of 9 and 12.
    Who am I?     36
  4. I am the largest composite number which is less than 20.
    Who am I?     18
  5. I am the largest prime number which, when rounded to the nearest ten, is 40.
    Who am I?     43

  6. I am the only prime number between 48 and 58.
    Who am I?     53
  7. I am an even number greater than 7.   I am also a common factor of 12 and 36.
    Who am I?     12
  8. I am the largest composite number which, when rounded to the nearest ten, is 40.
    Who am I?    44
  9. I am an odd composite number.   When rounded to the nearest ten, you get 10.
    Who am I?    9
  10. I am between 20 and 50.   I am a multiple of 13.   I am odd.
    Who am I?    39

  11. I am an even prime number.
    Who am I?    2
  12. I am the smallest number having exactly six distinct prime factors.
    Who am I?    30,030
  13. I am the only common factor of 251 and 673.
    Who am I?     1
  14. Dividing a number by me gives the same answer as multiplying the number by 3.
    Who am I?     1/3
  15. I am the only common factor of 211 and 811.
    Who am I?     1

  16. If you multiply me by 9, you get 45.
    Who am I?     5
  17. I am the smallest even number which, when rounded to the nearest hundred, is 300.
    Who am I?    250
  18. If you divide me by 1/4, you get 7.
    Who am I?     7/4
  19. I have only one multiple.
    Who am I?     1
  20. I am between 20 and 30.   I am a multiple of 7.   I am even.
    Who am I?     28

  21. I am a common multiple of 6 and 9.   I am a factor of 18.
    Who am I?     18
  22. I am an odd number.   I am a multiple of 5.
    When you round me to the nearest ten, you get 30.
    Who am I?     25
  23. I am the least common multiple of 6 and 9.
    Who am I?     18
  24. I am the greatest common factor of 30 and 48.
    Who am I?     6
  25. I have exactly three prime factors.   Two of my three factors are even.
    When you round me to the nearest ten, you get 50.
    Who am I?    52
    (Note: 45 and 50 also have 3 prime factors and round to 50,
    but they have 2 odd factors)