How it is calculated
The GCD is found by Euclid’s algorithm: the larger number is replaced by the remainder until that remainder is zero. The LCM is the product of the absolute values, divided by the GCD.
LCM(a, b) = |a × b| / GCD(a, b)
Where the numbers come from
- First number
- Second number
Example
12 and 18. GCD 6, LCM 36.
Questions
Can the numbers be fractional?
No. The school GCD is defined for integers.
What about zero?
GCD(0, 5) = 5. GCD(0, 0) is undefined.
For three numbers?
Find the GCD of the first two, then the GCD of that result and the third number. The LCM works the same way.