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From: matloff@bizet.Berkeley.EDU (Norman Matloff)
Newsgroups: comp.arch
Subject: Re: Trachtenberg System of Math
Message-ID: <16053@agate.BERKELEY.EDU>
Date: 27 Oct 88 01:58:31 GMT
References: <6232@june.cs.washington.edu> <6821@pasteur.Berkeley.EDU>
Sender: usenet@agate.BERKELEY.EDU
Reply-To: matloff@iris.ucdavis.edu (Norm Matloff)
Organization: EECS, UC Davis
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In article <6821@pasteur.Berkeley.EDU> aho@cory.Berkeley.EDU.UUCP (Alex Ho) writes:
*In article <6232@june.cs.washington.edu> pardo@cs.washington.edu (David Keppel) writes:
*>As a kid I read part of a book called "The Trachtenberg System of
*>Math" or some such.  The basic idea was that there were several rules
*>that could be applied to *all* numbers to do *very* fast (linear in
*>number of digits?) multiplies and multi-row adds. 

*this system sounds pretty interesting.
*do you have a reference to the original source,
*a book or a more recent magazine article, by any
*chance.

I think that the title is VERY close to what David remembers it as.
However, as I recall, the system was NOT as far-reaching as David
seems to be implying.  It consisted of a bunch of specialized rules
(e.g. similar to the well-known fact that a number is divisible by 3
iff the sum of its digits is divisible by 3) that did NOT apply to
all situations.  But maybe my memory is wrong on this.

Interesting sidelight:  Trachtenberg invented his system while in
prison, I think a Nazi prison.  He whiled away the hours by inventing
all these speedy-arithmetic rules.

    Norm