
RE: Teaching Dev Mathematics Conceptually: practical ideas
Posted:
Feb 18, 2009 11:37 PM


It is just to make it a little easier to understand. I also told students that most people would use minus to mean negative, opposite of, and subtract since they are all indicated by "". So many students think x is negative that is worth giving them some different words to use in the different contexts to help them keep it straight.
wayne
Quoting Martin Weissman <mathprof@hotmail.com>:
> > What's the difference whether a "" > means minus or 'the opposite of' > if the answers are the same? > > Besides, don't 'minus' > and 'the opposite of' actually > mean the same thing? > > > Professor Martin Weissman > > Prof Weissman's Software > > 246 Crafton Avenue > > Staten Island, NY 10314 > > Cell: 3475287837 > > mathprof@hotmail.com > > www.math911.com > > > > > > > > > > > >> From: kathy.mowers@kctcs.edu >> To: mahlerp@middlesex.mass.edu; mathedcc@mathforum.org >> Date: Wed, 18 Feb 2009 16:54:42 0500 >> Subject: RE: Teaching Dev Mathematics Conceptually: practical ideas >> >> At one point, according to what I've seen there was a movement to >> try to use different symbols to mean "the opposite" and "minus." >> It didn't catch on, obviously. In one case, the opposite was >> higher on the line and smaller than the minus. I cannot reproduce >> it on the keyboard. >> >> Original Message >> From: ownermathedcc@mathforum.org >> [mailto:ownermathedcc@mathforum.org] On Behalf Of Philip Mahler >> Sent: Wednesday, February 18, 2009 3:45 PM >> To: mathedcc@mathforum.org >> Subject: Re: Teaching Dev Mathematics Conceptually: practical ideas >> >> On 2/18/09 3:32 PM, "wmackey" <wmackey@uark.edu> wrote: >> >> > Well, I don't think the expression 3^2 is undefined if  is properly >> > defined. It should be read as the opposite of 3^2 which is clearly >> > negative 9 or 9. The  symbol has three different meanings depending >> > on context. In front of a natural number it means "negative", in >> > front of anything else it means "opposite". If it is between 2 things >> > it means subtract. Since no books except mine bother to define the >> > symbol it leaves everyone confused. >> > >> > wayne >> >> >> I like the fact that you confront this situation head on. You are saying, I >> think, that  in front of any expression where it doesn't mean subtraction, >> or not in front of a single numeral, means (expression). In some ways it >> implies a symbol of grouping. I guess it could be extended to even a numeral >> since the opposite of what a numeral represents is a negative number? >> >> That can add a little extra work to something like 6(4), since you have to >> think of it as [6(4)] rather than the product of two negatives. But of >> course in practice it probably would not be an impediment, people would just >> think of it as the product of two negatives, and I grant it helps immensely >> with 3^2. Though demonstrably one cannot depend on entering 3^2 into >> calculating devices and getting the defined result. But at least it tells >> one to enter it as (3^2). >> >> I might be able to live with that because that just might stick with >> students (I imagine that is your experience?). And I realize that everyone >> else on the list lives with 3^2 without a problem already. :) >> >> Phil >> >> **************************************************************************** >> * To post to the list: email mathedcc@mathforum.org * >> * To unsubscribe, email the message "unsubscribe mathedcc" to >> majordomo@mathforum.org * >> * Archives at http://mathforum.org/kb/forum.jspa?forumID=184 * >> **************************************************************************** >> **************************************************************************** >> * To post to the list: email mathedcc@mathforum.org * >> * To unsubscribe, email the message "unsubscribe mathedcc" to >> majordomo@mathforum.org * >> * Archives at http://mathforum.org/kb/forum.jspa?forumID=184 * >> **************************************************************************** >
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