GCF for 15 and 20

"Greatest Common Factor" Calculator

Greatest Common Factor of

and

What is the Greatest common Divisor of 15 and 20?

Answer: GCF of 15 and 20 is 5

(Five)

Finding GCF for 15 and 20 using all factors (divisors) listing

The first method to find GCF for numbers 15 and 20 is to list all factors for both numbers and pick the highest common one:

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

All factors of 20: 1, 2, 4, 5, 10, 20

So the Greatest Common Factor for 15 and 20 is 5

Finding GCF for 15 and 20 by Prime Factorization

The second method to find GCF for numbers 15 and 20 is to list all Prime Factors for both numbers and multiply the common ones:

All Prime Factors of 15: 3, 5

All Prime Factors of 20: 2, 2, 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 15 and 20

Related Calculations

See Also

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 15 and 20? (The answer is: 5). Select the first number (e.g. '15') and the second number (e.g. '20'). 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
1201
2202
3201
4204
5205
6202
7201
8204
9201
102010
11201
12204
13201
14202
15205
16204
17201
18202
19201
202020
21201
22202
23201
24204
25205
26202
27201
28204
29201
302010

FAQ

What is the Greatest common Divisor of 15 and 20?

GCF of 15 and 20 is 5

See Also