Greatest common factor calculator

GCF(18, 30) = 2×3 = 6

Calculation

1. Find the prime factorization of each of the number.
2. Find minimal (common) exponent of each prime factor.
3. Multiply all the prime factors from step 2 together to get the final result.
4. If no prime factors are common to all numbers, the GCD is 1.

18 = 2×3²

30 = 2×3×5

GCF = 2×3 = 6

Division by the greatest common divisor

18 / 6 = 3

30 / 6 = 5

What is GCF?

The greatest common factor (gcf), or highest common factor (hcf), of two or more integers (at least one of which is not zero), is the largest positive integer that divides the numbers without a remainder. It is the highest number that divides exactly into two or more numbers. It is the "greatest" thing for simplifying fractions. The greatest common factor is useful for reducing fractions to be in lowest terms.

See divisors of numbers 6, 18, 30.

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