Least Common Multiple (LCM)

  • The smallest number that is common to the multiples of two or more positive integers is the Least Common Multiple (LCM)
  • Example: the multiples of 3 are 3, 6, 9, 12, 15, …, and the multiples of 4 are 4, 8, 12, 16, …, as a result the LCM(3,4) =12
  • As noted in the example, the LCM can be found by listing the multiples of each positive integer in question or by Prime Factorization of each positive integer in question
  • If there are only two positive integers in question a and b, the LCM(a, b) is equal to the product of a and b divided by the Greatest Common Factor (GCF) between a and b, or LCM (a,b) =
  • The Least Common Denominator (LCD) of two or more fractions is equivalent to the LCM of the denominators
  • Application: Finding the LCD of two or more fractions
  • Application: Determining the quantity of a finished product that should be manufactured to avoid wasting component parts that are packaged or sold in different quantities.
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