Is LCM the same as LCD?
LCD means least common denominator — it's the LCM of the denominators when you're adding fractions. Same number, different job title.
Why won't the tool accept 0 or negatives?
LCM is defined on positive integers in school math. Zero is a special case (some texts say LCM(a,0)=0); negatives have the same absolute LCM as their positives. We keep the interface to positive integers so homework answers match what teachers expect.
Can I enter decimals?
No — LCM is an integer concept here. If you have decimals, clear the decimal point by multiplying through (e.g. work with 1.5 and 2 as 3 and 4 after ×2), then scale back.
How accurate is the calculator?
Exact for integers within the input limit. We use integer GCD arithmetic, not floating-point approximation. Results stay precise until numbers get large enough that JavaScript's number type (safe integers up to 253) would overflow — which is why we cap inputs.
Do you store the numbers I type?
No. Everything runs in your browser. Nothing is sent to a server for calculation.
What's the difference between GCD and LCM?
GCD is the biggest number that divides all inputs. LCM is the smallest number that all inputs divide into. For two numbers they multiply to |a×b|.
Is this site free for classroom use?
Yes. Link it, project it, put it on a worksheet. Attribution appreciated but not required.