最小公倍数計算ツール
The detailed guide below is currently available in English.
What the least common multiple is good for
The least common multiple of two numbers is the smallest number both divide evenly. Multiples of 4 are 4, 8, 12, 16… and multiples of 6 are 6, 12, 18…, so LCM(4, 6) = 12 — the first value on both lists. The shortcut this calculator uses pairs the LCM with the greatest common factor: multiplying the two always gives the original product, so LCM = (a × b) ÷ GCF. Its most familiar job is adding fractions with different denominators, where the LCM of the denominators becomes the lowest common denominator.
よくある質問
How is the LCM different from the GCF?
The GCF is the largest number that divides both inputs — it is never bigger than the smaller input. The LCM is the smallest number both inputs divide — never smaller than the larger one. For 12 and 18 the GCF is 6 and the LCM is 36.
Why does the GCF × LCM check always equal the product?
It is a standard identity for two numbers: every prime’s power shows up once in the GCF and once in the LCM, so together they rebuild a × b exactly. The calculator prints the check so you can verify it yourself.