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Math

GCF & LCM Calculator

Find the Greatest Common Factor (GCF) and Least Common Multiple (LCM) of two or more numbers.

GCF & LCM
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GCF
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LCM
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Numbers
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GCF vs LCM

The GCF (Greatest Common Factor) is the largest number that divides all the given numbers evenly. The LCM (Least Common Multiple) is the smallest number that is a multiple of all the given numbers.

GCF(12, 18) = 6 (largest divisor of both) LCM(12, 18) = 36 (smallest common multiple) GCF x LCM = Product of the two numbers

Frequently Asked Questions

GCF is used to simplify fractions — divide numerator and denominator by their GCF. Example: 12/18 simplified = 12/6 / 18/6 = 2/3. Also used in algebra for factoring polynomials.
LCM is used to find a common denominator when adding or subtracting fractions. Example: to add 1/4 + 1/6, find LCM(4,6)=12, then convert: 3/12 + 2/12 = 5/12.