GCF for 9 and 15

What is the Greatest common Divisor of 9 and 15?

Answer: GCF of 9 and 15 is 3

(Three)

Finding GCF for 9 and 15 using all factors (divisors) listing

The first method to find GCF for numbers 9 and 15 is to list all factors for both numbers and pick the highest common one:

All factors of 9: 1, 3, 9

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

So the Greatest Common Factor for 9 and 15 is 3

Finding GCF for 9 and 15 by Prime Factorization

The second method to find GCF for numbers 9 and 15 is to list all Prime Factors for both numbers and multiply the common ones:

All Prime Factors of 9: 3, 3

All Prime Factors of 15: 3, 5

As we can see there is only one Prime Factor common to both numbers. It is 3

So 3 is the Greatest Common Factor of 9 and 15

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 9 and 15? (The answer is: 3). Select the first number (e.g. '9') 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

GCF Table

Number 1Number 2GCF
1151
215
315
415
515
615
715
815
915
1015
1115
1215
1315
1415
151515
16151
17151
1815
19151
2015
21153
22151
23151
24153
2515
26151
27153
28151
29151
301515

FAQ

What is the Greatest common Divisor of 9 and 15?

GCF of 9 and 15 is 3