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Topic: neg * neg = pos; why?
Replies: 26   Last Post: Jul 31, 1997 3:22 PM

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Frances Rosamond

Posts: 9
Registered: 12/3/04
Re: neg * neg = pos; why?
Posted: Jul 25, 1997 2:38 PM
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Your comment about your daughters reminds me of a old story: A famous
person (I forget who) was giving a lecture and said, "Two negatives equal a
positive but two positives never equal a negative." Then someone in the
audience disparagingly called out, "Yah, Yah."
Fran Rosamond
Department Chair
Mathematics and Natural Sciences
National University
11255 North Torrey Pines Road
La Jolla, CA 92037

At 09:58 AM 7/25/97 -0500, you wrote:
>This seems to be worth sharing because it's how they're learning it in the
>"real world" of public school.
>My 12 and 14 year old daughters say this:
>A negative times a negative equals a positive because they "cancel each
>other out." They compare it to using double negatives when speaking.
>Is this conceptual, algorithmic, or ?
>Stuart Moskowitz W (707) 826-4181
>Dept. of Mathematics H (707) 445-5795
>Humboldt State University FAX (707) 826-3140
>Arcata, CA 95521

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