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even number (Definition)

Definition Suppose $k$ is an integer. If there exists an integer $r$ such that $k=2r+1$ then $k$ is an odd number. If there exists an integer $r$ such that $k=2r$ then $k$ is an even number.

The concept of even and odd numbers are most easily understood in the binary base. Then the above definition simply states that even numbers end with a $0$ and odd numbers end with a $1$

Properties

  1. Every integer is either even or odd. This can be proven using induction, or using the fundamental theorem of arithmetic.
  2. An integer $k$ is even (odd) if and only if $k^2$ is even (odd).




"even number" is owned by mathcam. [ full author list (2) | owner history (2) ]
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See Also: odd number

Also defines:  odd number, even integer, odd integer, even, odd

Attachments:
singly even number (Definition) by CompositeFan
doubly even number (Definition) by 1and2and4
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Cross-references: fundamental theorem of arithmetic, induction, base, binary, integer
There are 695 references to this entry.

This is version 7 of even number, born on 2003-09-05, modified 2006-08-10.
Object id is 4703, canonical name is EvenNumber.
Accessed 37494 times total.

Classification:
AMS MSC03-00 (Mathematical logic and foundations :: General reference works )
 11-00 (Number theory :: General reference works )

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