LCM and GCF calculator
Lowest common multiple and greatest common factor (HCF) of a list of whole numbers.
How this calculator works
The GCF uses Euclid's algorithm: keep replacing the larger number with the remainder until it reaches zero. LCM(a, b) = a ÷ GCF(a, b) × b, applied across the list.
Worked example: for 12, 18 and 30 the GCF is 6 and the LCM is 180. The LCM is handy for common denominators: 1/12 + 1/18 uses 36.
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