what is the proof for divisibility tests in general, and in particular how are they derived.(adsbygoogle = window.adsbygoogle || []).push({});

for example, i know that in base m, if the sum of the digits are a multiple of m-1, then m-1 is a factor. how tests like alternating digits having equal sums found?

does a test exist for every number?

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# Proof for divisability tests

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