Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

Topic: Why?
Replies: 52   Last Post: Oct 30, 2012 9:38 PM

 Messages: [ Previous | Next ]
 Paul A. Tanner III Posts: 5,920 Registered: 12/6/04
Re: Why?
Posted: Oct 26, 2012 11:11 PM

On Fri, Oct 26, 2012 at 8:57 PM, Robert Hansen <bob@rsccore.com> wrote:
>
> On Oct 26, 2012, at 12:40 AM, Wayne Bishop <wbishop@calstatela.edu> wrote:
>
> I have no objection to using expressions of this type even in second and
>
>
> Define "use".
>
> I have no objection to formulas, where the letters are simply placeholders
> and the only subsequent step is to replace them with numbers. To pretend
> that they are algebraic expressions, in the minds of the child to be
> manipulated algebraically, is not developmentally sound.
>

Who says other than you? Name names.

Do you think that they are able to grasp the idea of subtraction as the inverse of addition if and only if it is not written using the letters of the alphabet?

Can't at least many of them understand that 10 - 3 = 7 is true when and only when and 10 = 7 + 3 is true?

Can't at least many of them understand that we can replace these numbers in such examples with letters of the alphabet a,b,c to express the idea being true for all numbers, that a - b = c is true when and only when a = c + b is true?

And if so, can't they all see the visual attribute of the written expression of the definition of subtraction as the inverse of addition, that a number or variable looks like it moves back and forth the equality symbol and the sign of the number changes as it does?

Date Subject Author
10/23/12 Robert Hansen
10/23/12 Haim
10/23/12 Clyde Greeno
10/23/12 Dave L. Renfro
10/23/12 Paul A. Tanner III
10/23/12 Robert Hansen
10/23/12 Paul A. Tanner III
10/23/12 Robert Hansen
10/24/12 Paul A. Tanner III
10/24/12 Robert Hansen
10/24/12 Paul A. Tanner III
10/24/12 Robert Hansen
10/24/12 Paul A. Tanner III
10/24/12 Robert Hansen
10/24/12 Paul A. Tanner III
10/24/12 Robert Hansen
10/24/12 Paul A. Tanner III
10/25/12 Robert Hansen
10/25/12 Louis Talman
10/26/12 Wayne Bishop
10/25/12 Paul A. Tanner III
10/27/12 kirby urner
10/27/12 Robert Hansen
10/27/12 kirby urner
10/25/12 Robert Hansen
10/25/12 Paul A. Tanner III
10/23/12 Jonathan J. Crabtree
10/25/12 Robert Hansen
10/24/12 GS Chandy
10/26/12 Wayne Bishop
10/26/12 Robert Hansen
10/27/12 Paul A. Tanner III
10/27/12 Robert Hansen
10/27/12 Paul A. Tanner III
10/27/12 Robert Hansen
10/27/12 kirby urner
10/28/12 Paul A. Tanner III
10/28/12 Robert Hansen
10/28/12 Paul A. Tanner III
10/27/12 Wayne Bishop
10/29/12 Joe Niederberger
10/29/12 Joe Niederberger
10/29/12 Robert Hansen
10/30/12 Louis Talman
10/30/12 Robert Hansen
10/30/12 Paul A. Tanner III
10/30/12 Louis Talman
10/30/12 Robert Hansen
10/30/12 Louis Talman
10/30/12 Robert Hansen
10/30/12 Louis Talman
10/30/12 Clyde Greeno @ MALEI
10/30/12 kirby urner