<html> <head> <style></style> </head> <body class='hmmessage'><div dir='ltr'> <div><br></div>Hi,<div><br></div><div>The touch scrren allows manipulate the abacus activity like an real abacus...</div><div><br></div><div>And when you have some practice with your fingers.. you can will be more </div><div>quick than a calculator! I see the Japanesse children make it with incredible speed!</div><div><br></div><div><a href="http://www.youtube.com/watch?v=yj7XbnYrIk0&feature=related">http://www.youtube.com/watch?v=yj7XbnYrIk0&feature=related</a></div><div><br></div><div><a href="http://www.youtube.com/watch?v=KwY9oazPqGg&feature=related">http://www.youtube.com/watch?v=KwY9oazPqGg&feature=related</a><br></div><div><br></div><div>Regards</div><div><br></div><div>Alan<br><br><div>> Date: Sun, 9 Oct 2011 11:20:07 -0700<br>> From: yoshiki@vpri.org<br>> To: walter.bender@gmail.com<br>> CC: iaep@lists.sugarlabs.org<br>> Subject: Re: [IAEP] Abacus suggestions<br>> <br>> Hi, Walter,<br>> <br>> At Sun, 9 Oct 2011 08:57:51 -0400,<br>> Walter Bender wrote:<br>> > <br>> > > - As you can see, the default 1's digit (the big white dots) is in<br>> > > the middle, not the far right. That makes sense to tell that<br>> > > there are numbers smaller than 1 and for the idea of power of 10.<br>> > > (It is often a good technique to slide the decimal point, so I<br>> > > first thought the red triangle to mean this, but it is something<br>> > > else.)<br>> > <br>> > The red triangle is a mark found on many Chinese abaci. It is useful<br>> > for to keeping track of place while doing multiplication and division.<br>> <br>> Ok. The scheme on the wiki is different from what I know. Which<br>> clears the used digits of multiplier as you go and that serves as the<br>> tracker. But I see that if you have it there, it can be used for such<br>> a purpose.<br>> <br>> > > - For a non-"5 and 4" abacus, this is not simple, but then why kids<br>> > > in the 21st century need to learn Mayan arithmetic...<br>> > <br>> > My goal with the abacus was primarily to introduce the idea of<br>> > multiple representations.<br>> <br>> Ok... It seems to me that these different traditional ones are tied<br>> to the way they say or write numbers. In other words, the abacus in<br>> that culture feels natural, but once we try to map the numberto base<br>> 10 arabic notation, it requires some extra mind work. Which may be<br>> about this "multiple representations".<br>> <br>> > > - So, there are some 90 combinations of two one digit number<br>> > > additions. Some require 5's compliment arithmetic (adding 4 to 2<br>> > > is subtracting 1 but then adding 5, etc.) or 10's (if it is the<br>> > > right terminlogy.) Abacus was about building the muscle memory<br>> > > for these 90 patterns of additions. Some of these require you to<br>> > > move both index finger and thumb at the same time. After<br>> > > acquiring this muscle memory, you can do any additions without<br>> > > thinking, and that is the point of abacus. But now, "doing<br>> > > additions without thining" is easier with electronic calculators.<br>> > > At the same time, the Abacus activity is not set up for learning<br>> > > about this part of idea (and XO is not multi touch, so you can't<br>> > > build the muscle memory).<br>> > <br>> > I haven't played with the abacus on the touch-screen XO yet... but it<br>> > is not multitouch. Muscle memory is not something we can do much with<br>> > on that hardware :P<br>> <br>> Hmm, too bad. The real abacus as an artifact feels good. We ride<br>> on it like a skate board, too.<br>> <br>> > > ----------------<br>> > ><br>> > > - There is a bug when I tried to make my own abacus. If there is a<br>> > > number already on abacus, changing the board made some beads stuck<br>> > > outside.<br>> > <br>> > I thought I fixed that bug in a recent release. What version are you using?<br>> <br>> It is from "508dx Dextrose 2 International".<br>> <br>> -- Yoshiki<br>> _______________________________________________<br>> IAEP -- It's An Education Project (not a laptop project!)<br>> IAEP@lists.sugarlabs.org<br>> http://lists.sugarlabs.org/listinfo/iaep<br></div></div> </div></body> </html>