GCF and LCM Calculator

The greatest common factor (GCF) is the largest number that divides all of your numbers. The least common multiple (LCM) is the smallest number they all divide into.

Type a number and the answer appears straight away.

Your answer

Greatest common factor6

Least common multiple
180

The math behind it: GCF and LCM

LCM(a, b) = a x b / GCF(a, b)

Use the GCF to simplify fractions and the LCM to find a common denominator. For 12, 18 and 30 the GCF is 6 and the LCM is 180.

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