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Alternating sum

Revision as of 14:11, 22 August 2006 by Mgao (talk | contribs)
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The alternating sum of a numbers digits, mentioned in the divisibility rule you were recently viewing, is, if the number is $n_0n_1n_2n_3n_4n_5...$, $n_0-n_1+n_2-n_3+n_4-n_5+...$.

In short, it is the sum of the digits with alternating signs.

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