GCD & LCM Calculator
Greatest common divisor and lowest common multiple, with factors.
How it works
The GCD is the largest number dividing all of them; the LCM is the smallest they all divide into.
Euclid's algorithm finds the GCD without factorising: replace the larger number with the remainder of dividing it by the smaller, and repeat until one is zero. It is over two thousand years old and still the fastest method known. The LCM follows from it, since GCD x LCM = the product of the pair.