Wednesday, July 1, 2015

Touch decimals: Part 1: References

New Touch decimals: free Android app: Part I

This is the application with a longer history among which I developed in
The first version, made after two failed attempts was published in 1997:
I named it nummòlt, and in fact was the fundational application of
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 page:
(Rebuilt by Jill Britton and Suzanne Alejandre of MathForum)
(Jacobo Bulaevsky died in 8/13/2004)

Brian Sutherland and his:
A rebuild of the Original:

In collaboration with Wendy Petti of MathCats, in 2003 we did the "Place Value Party"
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

(Here I must recommend the book: "Early Mathematics Learning: Selected papers of the POEM 2002 Conference": ) 

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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