|


Prime NumbersDate: 9/20/95 at 17:51:59 From: Anonymous Subject: Prime numbers What are prime numbers?
Date: 9/21/95 at 22:13:56
From: Doctor Ken
Subject: Re: Prime numbers
Hello!
A prime number is a positive number that has exactly two factors, 1 and
itself. For example, if we list the factors of 28, we have 1, 2, 4, 7,
14, and 28. That's six factors. If we list the factors of 29, we only
have 1 and 29. That's 2. So we say that 29 is a prime number, but 28
isn't.
Note that the definition of a prime number doesn't allow 1 to be a prime
number: 1 only has one factor, namely 1. Prime numbers have EXACTLY two
factors, not "at most two" or anything like that.
Here are the first few prime numbers:
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67,
71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149,
151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, etc.
-Doctor Ken, The Geometry Forum
|
Search the Dr. Math Library: |
[Privacy Policy] [Terms of Use]


Ask Dr. MathTM
© 1994-2013 The Math Forum
http://mathforum.org/dr.math/