1.   Find the greatest common factor of 168 and 288.
    A. 2 B. 36
    C. 24 D. 48
    Hint

  2.   What is the greatest common factor of 45, 75, and 135?
    A. 5 B. 9
    C. 15 D. 25
    Hint

  3.   Find the greatest common factor of 64ab3c2 and 48a2b2c.
    A. 16ab2c B. 16abc
    C. 8ab3c D. 8a2b2c2
    Hint

  4.   What is the greatest common factor of 18mn2, 54m4, and 80n3?
    A. 2mn2 B. 9mn
    C. 18m2n3 D. 2
    Hint

  5.   Are 12 and 25 relatively prime? Explain.
    A. Yes; 12 is even and 25 is odd.
    B. No; 12 and 25 are not prime numbers.
    C. No; 12 has three prime factors.
    D. Yes; 12 and 25 have no common factors.
    Hint