[FRIAM] This is how the Japanese multiply. (Math, not biology)

[barry.mackichan at mackichan.com]

This way of multiplying is isomorphic to what I learned in third grade. Multiply these numbers as you were taught. If your numbers have n and m digits, below the line in the multiplication there will be n m-digit numbers. (Ignoring carries for the sake of exposition), each of those n by m digits corresponds to a count of one of the small grids in the Japanese method. Hence the isomorphism.

Carries seem to b handled the same way in both methods.

— Barry
On Nov 3, 2018, 8:23 PM -0400, Frank Wimberly <wimberly3 at gmail.com>, wrote:
> "Real" and "real math" are two different things.  My definition of real math is exposition of the form "definition, theorem, proof".  When you figure out what "real" means, let me know.
>
> Frank
>
> -----------------------------------
> Frank Wimberly
>
> My memoir:
> https://www.amazon.com/author/frankwimberly
>
> My scientific publications:
> https://www.researchgate.net/profile/Frank_Wimberly2
>
> Phone (505) 670-9918
>
> > On Sat, Nov 3, 2018, 6:14 PM Nick Thompson <nickthompson at earthlink.net wrote:
> > > What!???? How could any mathematics not be REAL!  FRANK!  Defend yourself!
> > >
> > > NIck
> > >
> > > Nicholas S. Thompson
> > > Emeritus Professor of Psychology and Biology
> > > Clark University
> > > http://home.earthlink.net/~nickthompson/naturaldesigns/
> > >
> > > From: Friam [mailto:friam-bounces at redfish.com] On Behalf Of Prof David West
> > > Sent: Saturday, November 03, 2018 5:52 PM
> > > To: friam at redfish.com
> > > Subject: Re: [FRIAM] This is how the Japanese multiply. (Math, not biology)
> > >
> > > I have a couple of books on "Vedic Math" - a large set of techniques for how to calculate. This technique was among them.  Showed the books to Frank once, he was not impressed, "not real mathematics."
> > >
> > > davew
> > >
> > >
> > >
> > > On Sat, Nov 3, 2018, at 9:02 AM, Tom Johnson wrote:
> > > > https://www.facebook.com/637328420/posts/10156877698343421/
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> Meets Fridays 9a-11:30 at cafe at St. John's College
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