Fourth Grade Team Page

LCM & GCF

G. C. F.

Greatest Common Factor

-biggest number that is a factor of each number

L. C. M.

Least Common Multiple

-smallest number that is a common multiple of two or more #'

Greatest common factor examplesThe greatest common factor (GCF) of a set of numbers is the largest factor that all the numbers share. For example, 12, 20, and 24 have two common factors: 2 and 4. The largest is 4, so we say that the GCF of 12, 20, and 24 is 4. GCF is often used to find common denominators.

Least common multipleSal finds the LCM (least common multiple) of 12 and 36, and of 12 and 18. He shows how to do that using the prime factorization method, which is a just great!

GCF & LCM word problemsHere we have a couple of word problems--one searching for the least common multiple and the other for the greatest common factor. Just read them with us slowly and follow along. You'll get it.

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