# What is GCF for 9 and 13?

##### 2 Answers

Nov 3, 2016

GCF of

#### Explanation:

The factors of

as

Note that there are no common factors between them.

Such numbers are called **coprimes** or **relatively primes**.

GCF of such numbers is always

Nov 4, 2016

So GCF (greatest common factor) is 1

#### Explanation:

Using prime numbers as factors: also including 1

The only common factor is 1

So GCF (greatest common factor) is 1