# Relatively Prime

Pronunciation: /ˈrɛl.ə.tɪv.li praɪm/ Explain

Two positive integers greater than 1 are relatively prime if their greatest common factor is 1. To determine if two integers are relatively prime:

1. Find all common factors of the two integers.
2. If there are any common factors except 1, the two integers are not relatively prime.
3. If there are no common factors except 1, the two integers are relatively prime.

### How to Tell if Two Integers are Relatively Prime

1. Are 5 and 9 relatively prime?
• The factors of 5 are 1 and 5.
• The factors of 9 are 1, 3 and 9.
• There are no common factors, so 5 and 9 are relatively prime.
2. Are 6 and 15 relatively prime?
• The factors of 6 are 1, 2, 3, and 6.
• The factors of 15 are 1, 3, 5, and 15.
• Since 3 is a common factor, 6 and 15 are not relatively prime.
1. McAdams, David E.. All Math Words Dictionary, relatively prime. 2nd Classroom edition 20150108-4799968. pg 155. Life is a Story Problem LLC. January 8, 2015. Buy the book

McAdams, David E. Relatively Prime. 5/2/2019. All Math Words Encyclopedia. Life is a Story Problem LLC. http://www.allmathwords.org/en/r/relativelyprime.html.

### Revision History

5/2/2019: Changed equations and expressions to new format. (McAdams, David E.)
12/21/2018: Reviewed and corrected IPA pronunication. (McAdams, David E.)