Hi, The touch scrren allows manipulate the abacus activity like an real abacus... 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! http://www.youtube.com/watch?v=yj7XbnYrIk0&feature=related http://www.youtube.com/watch?v=KwY9oazPqGg&feature=related
Regards Alan > Date: Sun, 9 Oct 2011 11:20:07 -0700 > From: [email protected] > To: [email protected] > CC: [email protected] > 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 > about this "multiple representations". > > > > - 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 > > > number already on abacus, changing the board made some beads stuck > > > outside. > > > > I thought I fixed that bug in a recent release. What version are you using? > > It is from "508dx Dextrose 2 International". > > -- Yoshiki > _______________________________________________ > IAEP -- It's An Education Project (not a laptop project!) > [email protected] > http://lists.sugarlabs.org/listinfo/iaep
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