Classifying the Number One
Date: 11/27/98 at 11:53:22 From: Liz Lim Subject: Number theory Dear Dr. Math, My students have learned about prime and composite numbers. We are wondering what classification name fits the number 1. We know that it is neither prime nor composite. Some textbooks just say that 1 is a "special number." Can you help us? Sincerely, Liz Lim
Date: 11/27/98 at 12:54:37 From: Doctor Rob Subject: Re: Number theory The number 1 is a "unit"; that is, an integer whose reciprocal is also an integer. In the integers, only 1 and -1 are units, and you are restricting your attention to positive integers, so -1 is excluded. - Doctor Rob, The Math Forum http://mathforum.org/dr.math/
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