# [IAEP] Abacus suggestions

Walter Bender walter.bender at gmail.com
Sun Oct 9 15:25:51 EDT 2011

```On Sun, Oct 9, 2011 at 3:14 PM, Alan Jhonn Aguiar Schwyn
<alanjas at hotmail.com> wrote:
>
> Hi,
> The touch scrren allows manipulate the abacus activity like an real
> abacus...

As Yoshiki points out, without multitouch, you cannot use it in the
same what as a real abacus. Even with multitouch, you are missing much
of the tactile feedback you have with the physical object. So it is
doubtful that the Abacus activity could ever be manipulated at the
same speed as the real thing. But again, this is not really the point.

-walter

> And when you have some practice with your fingers.. you can will be more
> quick than a calculator! I see the Japanesse children make it with
> incredible speed!
>
> Regards
> Alan
>
>> Date: Sun, 9 Oct 2011 11:20:07 -0700
>> From: yoshiki at vpri.org
>> To: walter.bender at gmail.com
>> CC: iaep at lists.sugarlabs.org
>> Subject: Re: [IAEP] Abacus suggestions
>>
>> Hi, Walter,
>>
>> At Sun, 9 Oct 2011 08:57:51 -0400,
>> Walter Bender wrote:
>> >
>> > >  - As you can see, the default 1's digit (the big white dots) is in
>> > >    the middle, not the far right.  That makes sense to tell that
>> > >    there are numbers smaller than 1 and for the idea of power of 10.
>> > >    (It is often a good technique to slide the decimal point, so I
>> > >    first thought the red triangle to mean this, but it is something
>> > >    else.)
>> >
>> > The red triangle is a mark found on many Chinese abaci. It is useful
>> > for to keeping track of place while doing multiplication and division.
>>
>> Ok. The scheme on the wiki is different from what I know. Which
>> clears the used digits of multiplier as you go and that serves as the
>> tracker. But I see that if you have it there, it can be used for such
>> a purpose.
>>
>> > >  - For a non-"5 and 4" abacus, this is not simple, but then why kids
>> > >    in the 21st century need to learn Mayan arithmetic...
>> >
>> > My goal with the abacus was primarily to introduce the idea of
>> > multiple representations.
>>
>> Ok... It seems to me that these different traditional ones are tied
>> to the way they say or write numbers. In other words, the abacus in
>> that culture feels natural, but once we try to map the numberto base
>> 10 arabic notation, it requires some extra mind work. Which may be
>>
>> > >  - So, there are some 90 combinations of two one digit number
>> > >    additions.  Some require 5's compliment arithmetic (adding 4 to 2
>> > >    is subtracting 1 but then adding 5, etc.) or 10's (if it is the
>> > >    right terminlogy.)  Abacus was about building the muscle memory
>> > >    for these 90 patterns of additions.  Some of these require you to
>> > >    move both index finger and thumb at the same time.  After
>> > >    acquiring this muscle memory, you can do any additions without
>> > >    thinking, and that is the point of abacus.  But now, "doing
>> > >    additions without thining" is easier with electronic calculators.
>> > >    At the same time, the Abacus activity is not set up for learning
>> > >    about this part of idea (and XO is not multi touch, so you can't
>> > >    build the muscle memory).
>> >
>> > I haven't played with the abacus on the touch-screen XO yet... but it
>> > is not multitouch. Muscle memory is not something we can do much with
>> > on that hardware :P
>>
>> Hmm, too bad. The real abacus as an artifact feels good. We ride
>> on it like a skate board, too.
>>
>> > > ----------------
>> > >
>> > >  - There is a bug when I tried to make my own abacus.  If there is a
>> > >    outside.
>> >
>> > I thought I fixed that bug in a recent release. What version are you
>> > using?
>>
>> It is from "508dx Dextrose 2 International".
>>
>> -- Yoshiki
>> _______________________________________________
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>

--
Walter Bender
Sugar Labs
http://www.sugarlabs.org
```