Proposition: Prop. 9.23: Sum of Odd Number of Odd Numbers is Odd
Euclid's Formulation
If any multitude whatsoever of odd numbers is added together, and the multitude of them is odd, then the whole will also be odd.
 For let any multitude whatsoever of odd numbers, $AB$, $BC$, $CD$, lie together, and let the multitude of them be odd.
 I say that the whole, $AD$, is also odd.
Modern Formulation
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Table of Contents
Proofs: 1
Mentioned in:
Proofs: 1 2
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References
Adapted from (subject to copyright, with kind permission)
 Fitzpatrick, Richard: Euclid's "Elements of Geometry"
Adapted from CC BYSA 3.0 Sources:
 Prime.mover and others: "Pr∞fWiki", https://proofwiki.org/wiki/Main_Page, 2016