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Topic: Proportional Reasoning (related to April 24 webinar)
Replies: 3   Last Post: Apr 12, 2012 11:56 AM

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Bill Marsh

Posts: 350
From: Port Angeles, WA
Registered: 12/22/08
Re: Proportional Reasoning (related to April 24 webinar)
Posted: Apr 12, 2012 11:08 AM
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FWIW, I think Jack Rotman right to trace the importance of
proportional reasoning back to working with quantities. Things like
changing from kilometers to miles per hour.

The comparison of quantities approach to number concept development is
related to this.

I wish I could find the second part of the paper below on the web. It
deals with how we build quantities multiplicatively and is closer to
Jack's topic. The articles are, as we would expect, wonderful. Part
1 is at

MAA Writing Award 1969 "The Mathematics of Physical Quantities" by
Hassler Whitney
in The American Mathematical Monthly, vol. 75, 1968, pp. 115-138, 227-256
About the Author: Hassler Whitney was at the Institute for Advanced
Study, Princeton University, at the time of publication.

Bill Marsh

2012/4/12 Jack Rotman <>:
> If you are interested in what might be meant by ?proportional reasoning?,
> you can take a look at a post on my blog at

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