1.   Based on the factor trees, what is the greatest common factor of 8 and 20?
    A. 8 B. 20
    C. 2 D. 4
    Hint

  2.   What is the greatest common factor of 16x2 and 12x?
    A. 4x B. 4x2
    C. 16x2 D. 12x
    Hint

  3.   What is the greatest common factor of 64 and 40?
    A. 2 B. 8
    C. 20 D. 4
    Hint

  4.   What is the greatest common factor of 36, 54, and 90.
    A. 18 B. 36
    C. 6 D. 9
    Hint

  5.   What is the greatest common factor of 14p2q and 42p3q2?
    A. 14pq B. 7p2q2
    C. 14p2q D. 7pq
    Hint