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Topic: Simplifying Algebraic Expressions with Subtracted Expressions
Replies: 67   Last Post: Nov 25, 2013 12:57 PM

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 Pam Posts: 1,507 Registered: 12/6/04
Re: Simplifying Algebraic Expressions with Subtracted Expressions
Posted: Nov 17, 2013 7:42 PM

Posted: Nov 17, 2013 2:08 PM by Bob:
>
> Hold on! I resemble these remarks, that's my
> approach!:)

No, that is the Singapore Primary Mathematics approach.

>
> I didn't have a problem with diagraming as a way to
> help students realize the mathematical context of the
> problem. It was when you were using the bars as a
> gimmick with which to compute fractions that I had a
> problem. I said label the bars 3/5 and 1 - 3/5 (or
> just 2/5) and let arithmetic and reasoning take its
> course. You were dividing the bar into fifths and
> then magically dividing those fifths into halves and
> shading this piece here and that piece over there.
> That was what I had a problem with. Yes, an
> illustration, but not a solving strategy.

Why, oh why, would I not use the information given?? 3/5 is three fifths! "Magically"? There is no magic involved, simply an understanding of fractions!

>
> > See? Simply algebra but without having to know how
> to do algebraic manipulations with variable letters.
>
> I don't understand what you mean?

An algebra mirror then. The solution via bar diagrams mirrors the algebraic solution. Although, since in both we are manipulating unknowns, simply with different representations, I think algebra is not such a stretch.

Pam

Date Subject Author
11/11/13 MVTutor
11/11/13 Robert Hansen
11/12/13 Bishop, Wayne
11/12/13 MVTutor
11/13/13 Jonathan J. Crabtree
11/13/13 Bishop, Wayne
11/14/13 Joe Niederberger
11/14/13 Robert Hansen
11/14/13 Joe Niederberger
11/14/13 Robert Hansen
11/14/13 Joe Niederberger
11/14/13 Robert Hansen
11/14/13 Louis Talman
11/14/13 Joe Niederberger
11/14/13 Robert Hansen
11/14/13 Robert Hansen
11/16/13 Bishop, Wayne
11/16/13 Robert Hansen
11/14/13 Joe Niederberger
11/14/13 Robert Hansen
11/16/13 Bishop, Wayne
11/14/13 Pam
11/15/13 Robert Hansen
11/15/13 Joe Niederberger
11/15/13 Robert Hansen
11/15/13 Joe Niederberger
11/15/13 Joe Niederberger
11/15/13 Joe Niederberger
11/15/13 Robert Hansen
11/16/13 Bishop, Wayne
11/16/13 Robert Hansen
11/17/13 Bishop, Wayne
11/17/13 Robert Hansen
11/17/13 Bishop, Wayne
11/15/13 Joe Niederberger
11/15/13 Robert Hansen
11/15/13 Pam
11/15/13 Robert Hansen
11/15/13 Pam
11/16/13 Robert Hansen
11/16/13 Robert Hansen
11/16/13 Joe Niederberger
11/16/13 Robert Hansen
11/18/13 Louis Talman
11/21/13 Robert Hansen
11/21/13 Louis Talman
11/16/13 Pam
11/16/13 Robert Hansen
11/16/13 Pam
11/16/13 Robert Hansen
11/18/13 GS Chandy
11/17/13 GS Chandy
11/17/13 Pam
11/17/13 Robert Hansen
11/17/13 Pam
11/17/13 Robert Hansen
11/17/13 Pam
11/18/13 Robert Hansen
11/18/13 Robert Hansen
11/18/13 Pam
11/18/13 Robert Hansen
11/25/13 Bishop, Wayne
11/25/13 Robert Hansen
11/22/13 Joe Niederberger
11/25/13 Bishop, Wayne
11/23/13 GS Chandy
11/24/13 Robert Hansen
11/25/13 Bishop, Wayne