GCD & LCM Calculator
Greatest common divisor and least common multiple of any list of whole numbers.
How they're computed
The GCD uses the Euclidean algorithm: repeatedly replace the larger number with the remainder of dividing it by the smaller, until one hits zero. The LCM then falls out of the identity lcm(a, b) = a × b / gcd(a, b), applied across the list. For 24, 36 and 60 the GCD is 12 and the LCM is 360.
Where you actually use these
GCD (also called GCF) is what you divide by to reduce a fraction to lowest terms. LCM is the common denominator when adding fractions, and answers scheduling questions: two buses leaving every 24 and every 36 minutes coincide every 72 minutes, the LCM.