Comments on: Another math puzzle http://www.philhord.com/phord/another-math-puzzle/ Hobbies, family, life, science Wed, 20 Aug 2008 14:47:10 +0000 http://wordpress.org/?v=2.0.11 by: R.Kesavan http://www.philhord.com/phord/another-math-puzzle/#comment-2475 Fri, 04 Aug 2006 08:42:46 +0000 http://www.philhord.com/phord/another-math-puzzle/#comment-2475 Any number of the form ABCABC is not only divisible by 13, but also by 11 and 7. Here is the proof: ABCABC= ABC000+ABC = ABC(1000)+ABC = ABC(1000+1) =ABC(1001) =ABC(13X11X7) (because 1001 is a product of 7,11,and 13. Q.E.D. Any number of the form ABCABC is not only divisible by 13, but also by 11 and 7. Here is the proof:
ABCABC= ABC000+ABC
= ABC(1000)+ABC
= ABC(1000+1)
=ABC(1001)
=ABC(13X11X7) (because 1001 is a product of 7,11,and 13.

Q.E.D.

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