Wednesday, July 1, 2015

Touch decimals: Part 1: References

New Touch decimals: free Android app: Part I

Introduction:
This is the application with a longer history among which I developed in www.nummolt.com.
The first version, made after two failed attempts was published in 1997:
I named it nummòlt, and in fact was the fundational application of nummolt.com.
Nummòlt was a application developped in C ++, and it was my first OOP program:


It was one of many attempts in the nineties to represent numbers graphically to kids.
I will like to remember some of the contemporaries who tried to represent numbers graphically:

Jacobo Bulaevsky: and www.arcytech.org page:
(Rebuilt by Jill Britton and Suzanne Alejandre of MathForum)
(Jacobo Bulaevsky died in 8/13/2004)

http://britton.disted.camosun.bc.ca/baseten/b10blocks.html


Brian Sutherland and his: our-montessori.com:
A rebuild of the Original:



In collaboration with Wendy Petti of MathCats, in 2003 we did the "Place Value Party"
http://www.mathcats.com/explore/age/placevalueparty.html
With the "place value" shaped as floors of a virtual birthday cake:



In recent years, with the advent of affordable graphic tablets, there are new approaches:
Mainly: Ulrich  Kortenkamp (The creator of Cinderella). The Place Value Chart
https://itunes.apple.com/us/app/place-value-chart/id568750442


(Here I must recommend the book: "Early Mathematics Learning: Selected papers of the POEM 2002 Conference": https://books.google.es/books?id=Lui3BAAAQBAJ ) 

And also:
Christian Urff: Rechentablett:


After the appearance of all this, I saw the possibility of bringing my previous programs under the way to represent numbers used by Urff and Kortenkamp.

This is my free: "Touch decimals, Place value ±" for Android.
Place value structure seen before, adding tokens with sign, and with the ability to create the neutral element of the sum: pairs of tokens positive - negative that do not alter the final outcome of any addition or subtraction operation.


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