GCF of 5 and 15 (Greatest Common Factor)

"Greatest Common Factor" Calculator
Greatest Common Factor of
and

What is the Greatest Common Divisor of 5 and 15?

Answer

GCF of 5 and 15 is
5

(Five)

Finding GCF for 5 and 15 using all factors (divisors) listing

The first method to find GCF for numbers 5 and 15 is to list all factors for both numbers and pick the highest common one:

All factors of 5: 1, 5

All factors of 15: 1, 3, 5, 15

So the Greatest Common Factor for 5 and 15 is 5

Finding GCF for 5 and 15 by Prime Factorization

The second method to find GCF for numbers 5 and 15 is to list all Prime Factors for both numbers and multiply the common ones:

All Prime Factors of 5: 5

All Prime Factors of 15: 3, 5

As we can see there is only one Prime Factor common to both numbers. It is 5

So 5 is the Greatest Common Factor of 5 and 15

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About "Greatest Common Factor" Calculator

This calculator will help you find the greatest common factor (GCF) of two numbers. For example, it can help you find out what is the Greatest Common Divisor of 5 and 15? (The answer is: 5). Select the first number (e.g. '5') and the second number (e.g. '15'). After that hit the 'Calculate' button.
Greatest Common Factor (GCF) also known as the Greatest Common Divisor (GCD) or Highest Common Factor (HCF) - it is the largest positive integer that divides each of the integers with zero remainder.
"Greatest Common Factor" Calculator
Greatest Common Factor of
and

GCF Table

Number 1Number 2GCF
521
531
541
561
571
581
591
5105
5111
5121
5131
5141
5155
5161
5171
5181
5191
5205
5211
5221
5231
5241
5255
5261
5271
5281
5305
5311
5321
5331

FAQ

What is the Greatest Common Divisor of 5 and 15?

GCF of 5 and 15 is 5

How to find the GCF of 5 and 15?

You can find the GCF of 5 and 15 by listing all factors of both numbers and picking the greatest common one, or by prime factorization. The GCF of 5 and 15 is 5.

What prime factors do 5 and 15 share?

The prime factorizations of 5 and 15 have 5 in common, and multiplying those shared primes gives 5 — exactly the greatest common factor.

How does the GCF reduce the fraction 5/15?

Divide the numerator and the denominator by the GCF 5: 5 ÷ 5 = 1 and 15 ÷ 5 = 3. So 5/15 in lowest terms is 1/3.

See Also