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Home > CC1 > Chapter 3 > Lesson 3.2.4 > Problem 3-130

3-130.

Find the greatest common factor and the least common multiple of each of the following sets of numbers. Homework Help ✎

  1. 12 and 7

  • 7 is a prime number, so its only factor other than itself is 1.

    Their greatest common factor is 1. Can you find their least common multiple?

  1. 3, 15, and 9

  • To find the least common multiple, try finding multiples of 15 and checking
    whether they are also multiples of 3 and 9.

    The least common multiple is 45. Try finding the greatest common factor.

  1. 20 and 30

  • 10 is a factor of both of these numbers.