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From: eli@uw-june (Eli Messinger)
Newsgroups: net.math
Subject: Simple Division Properties
Message-ID: <548@uw-june>
Date: Wed, 24-Aug-83 16:05:26 EDT
Article-I.D.: uw-june.548
Posted: Wed Aug 24 16:05:26 1983
Date-Received: Fri, 26-Aug-83 03:51:00 EDT
Organization: U. Washington, Computer Sci
Lines: 19

There are actually quite a few "simple division properties" for base
10 arithmetic:

 	2: Last digit 0,2,4,6,8
	3: Digits sum to a number divisible by 3
	4: Last two digits (taken as a number twixt 00 and 99)
	   divisible by 4
	5: Last digit 0 or 5
	6: Divisible by 2 and 3
	7: ?
	8: ?
	9: Digits sum to a number divisible by 9
       10: Last digit 0

Does anybody have a proof of the rule for 3?  I had it in the notes from
a number theory course I took -- which I can no longer find.  (Send to me
by mail...)

	... uw-june!eli