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Topic: Is there a way to area model negative numbers?
Replies: 2   Last Post: Feb 3, 2005 2:37 AM

 Messages: [ Previous | Next ]
 Kevin Karplus Posts: 190 Registered: 12/6/04
Re: Is there a way to area model negative numbers?
Posted: Feb 2, 2005 11:12 PM

In article <akn2011gi1jk6srfquve2g9l2psjg2477f@4ax.com>, Scott Bryce wrote:
> If this is not the correct forum for this, please let me know.
>
> I am building a math worksheet generator. I am currently working on
> worksheets to practice comparing fractions. I want to provide an option
> to show area models of the two fractions. I also want to provide an
> option to include problems with negative numbers.
>
> Area models are easy. If the student is comparing 1/4 to 1/3, I can draw
> two same-size rectangles side by side. One is divided into 1/4s with 1/4
> shaded. The other is divided into 1/3s with 1/3 shaded. The student can
> see that the 1/3 shaded area is larger than the 1/4 shaded area.
>
> Is there a similar way to model the comparison when both fractions are
> negative? I could use the same models to show that 1/3 is more negative
> than 1/4, but I don't think that is intuitive.
>
> Number lines are an option. What other options are there?

Color coding (blue for +, red for -)

Above/below a zero line.
Left/right of a zero line.

Adding constant (comparing 1+ -1/3 with 1+ -1/4).

Football yardage (gains and losses)

------------------------------------------------------------
Kevin Karplus karplus@soe.ucsc.edu http://www.soe.ucsc.edu/~karplus
Professor of Biomolecular Engineering, University of California, Santa Cruz
(Senior member, IEEE) (Board of Directors, ISCB)
life member (LAB, Adventure Cycling, American Youth Hostels)
Effective Cycling Instructor #218-ck (lapsed)
Affiliations for identification only.

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Date Subject Author
2/2/05 Scott Bryce
2/2/05 Kevin Karplus
2/3/05 Bob