Unit 2: Common Multiples and Common Factors

2a. Find the greatest common factor and least common multiple of whole numbers

  • What is the Greatest Common Factor of a set of numbers?
  • What is the Least Common Multiple of a set of numbers?

A factor is a whole number that you can divide a given number by. When you have a set of 2 or more numbers, the greatest common factor is the largest number that you can divide all of the numbers in your set by. For example, the greatest common factor of 12 and 20 is 4, because 4 is the largest number that you can divide both 12 (12 /4 =3) and 20 (20/4=5) evenly by.

The least common multiple is the smallest number that a set of numbers is a factor of. If you have a set of numbers, the least common multiple is the smallest number that all the numbers in your set can be multiplied to get. For example, the least common multiple of 4 and 6 is 12, because 4 \times 3=12 and 6 \times 2=12. 12 is the smallest number that can be divided by both 4 and 6, making it the least common multiple.

To review, see:

  • [2.1 The Greatest Common Factor]
  • [2.2 The Least Common Multiple]

Unit 2 Vocabulary

This vocabulary list includes terms you will need to know to successfully complete the final exam.

  • factor
  • greatest common factor
  • least common multiple
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