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### Chisanbop: Advanced Counting on Fingers

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Date: 3/18/96 at 5:29:34
From: Harbin
Subject: Counting fingers

I saw on TV years ago kids in 1st grade doing advanced math by
counting on their fingers. They were using their fingers as some
kind of abacus or something. Does anybody know of this technique,
and where I can find out more about it?

Thanks,

Harbin Osteen
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Date: 6/24/96 at 20:20:26
From: Doctor Jodi
Subject: Re: Counting fingers

Hi Harbin!

There's a tutorial by Andy Harris on this method, called chisanbop,
on the Web at:

http://www.cs.iupui.edu/~aharris/chis/chis.html

Chisanbop is an easy, lightning-quick calculator developed by
can learn to use it in minutes. It requires two hands.

Try it yourself first. Place your hands palm-down on a table,
to right now, each of the four fingers on your left hand
equals ten; the left thumb equals fifty; the right thumb
equals five; and each of the four fingers on your right hand
equals one. Now construct different numbers on your own.
Two thumbs folded under could only equal 55; two index
fingers, 11.

Let's try a sample problem: 18 + 26. Show 18 by pressing down
the left index finger and the right thumb, index, middle, and
ring fingers.

Now: Think of 26 as 10, 10, 5, and 1. The first two 10s are
easy: Press down the middle and ring fingers on your left
hands. The 5 is the only tricky part; you exchange between
hands. Lift the right thumb (subtracting 5), then press down
your left pinky (adding 10, for a net gain of 5). For the 1,
press down the right pinky. Your hands now read 44 - the

And I was browsing the library the other day and found _The
Complete Book of Fingermath_  by Edwin M. Lieberthal (McGraw-Hill,
1979), which I recommend.

I hope this helps - please let us know if we can help again.

-Doctor Jodi,  The Math Forum

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