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Subject: "what is a number?"     Previous Topic | Next Topic
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literaryguy (Guest)
Jun-25-01, 09:15 AM (EST)
"what is a number?"
   Is zero a number? Is it an even number? How is "even number" defined?

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Charter Member
672 posts
Jun-25-01, 09:32 AM (EST)
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1. "RE: what is a number?"
In response to message #0
   A number is a member of a group of other items for which one or more opertations (like addition or multiplication) is defined that result in other members of the group. For example:

  1. Counting numbers: 1, 2, 3, ...
  2. Whole numbers: 1, 2, 3, ... and sometimes 0, 1, 2, 3, ...
  3. Integers: -2, -1, 0, 1, 2, ...
  4. Rational numbers: 1/2, -3/7, 0, ...

Zero is not a counting number, but it is integer, rational, real, complex number and many others.

The notion of evenness applies to integers. A number N is even when it's evenly divisible by 2, which means that

N = N/2 · 2.

Therefore, by definition, zero is an even number.

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