最大公約数・最小公倍数の計算機
16 と 24 の最大公約数は 8 です。この計算機は 2 つ以上の整数の最大公約数と最小公倍数を、素因数分解とあわせて求めます。
結果
値を入力して「計算」を押すと結果が表示されます。
公式
For two numbers, the GCD and LCM multiply to the product of the numbers.
この計算ツールの使い方
- Type the numbers, e.g. 12, 18, 30.
- Press Calculate to see the GCD, the LCM and each number’s prime factorisation.
解き方付き例題
GCD and LCM of 12 and 18
12 = 2² × 3 and 18 = 2 × 3².
GCD takes the lowest powers: 2 × 3 = 6. LCM takes the highest: 2² × 3² = 36.
The GCF of 16 and 24
16 = 2⁴ and 24 = 2³ × 3. The greatest common factor takes the shared primes at their lowest power: 2³ = 8.
The LCM takes every prime at its highest power: 2⁴ × 3 = 48.
Check: 8 × 48 = 384 = 16 × 24.
The GCF of 16 and 36
16 = 2⁴ and 36 = 2² × 3². The only shared prime is 2, at power 2: GCF = 4.
LCM = 2⁴ × 3² = 144. Check: 4 × 144 = 576 = 16 × 36.
よくある間違い
- Mixing up GCF and LCM: the GCF is never bigger than the smallest number; the LCM is never smaller than the largest.
- Using the highest power for the GCF: for 16 = 2⁴ and 24 = 2³ × 3 the GCF uses 2³, not 2⁴.
- Stopping at a common factor that isn’t the greatest: 4 divides 16 and 24, but 8 is bigger.
よくある質問
What is the GCF of 9 and 36?
9, because 9 divides 36 exactly (36 = 4 × 9). When one number divides the other, it is the GCF.
Are GCF, GCD and HCF the same?
Yes — greatest common factor (GCF), greatest common divisor (GCD) and highest common factor (HCF, the usual UK name) all mean the same number.
Is GCD the same as HCF or GCF?
Yes. Greatest common divisor, highest common factor and greatest common factor all mean the same thing.
Where is the LCM used?
Adding fractions uses the LCM of the denominators — the least common denominator.