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 Discussion: Roundtable Topic: Converting fractions to decimals and vice versa

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 Subject: RE: Converting fractions to decimals and vice versa Author: Mathman Date: Jan 7 2005
On Jan  6 2005, tackweed wrote:
> On Jan  6 2005, Gurmohan wrote:
> I am looking for math sites or
> tools explaining fractions and
> decimals and how one kind is
> converted into other.

> If you would like to see some things that I have used, here are some
> links you might try and see if they can give you some ideas:

<a
> href=" http://www2.whidbey.net/ohmsmath/webwork/OL_Text/fr_dec_pct.htm
> "> http://www2.whidbey.net/ohmsmath/webwork/OL_Text/fr_dec_pct.htm< ;/a>
> gives ome general overview information and illustrations.

<a
> href=" http://www2.whidbey.net/ohmsmath/pictures/frac2dec.gif ">
> http://www2.whidbey.net/ohmsmath/pictures/frac2dec.gif< ;/a>  shows a
> solution for fraction to decimal using a standard method.

<a
> href'" http://www2.whidbey.net/ohmsmath/webwork/javascript/fr2dec.html
> "> http://www2.whidbey.net/ohmsmath/webwork/javascript/fr2dec.html
> </a> is a simple tool that does the conversion.

<a
> href=" http://www2.whidbey.net/ohmsmath/webwork/javascript/frac2dec.htm ">
> http://www2.whidbey.net/ohmsmath/webwork/javascript/frac2dec.htm
> </a> will generate a worksheet with examples of how to set up the
> problem. (this is still in development so let me know if problems
> arise.)

<a
> href=" http://www2.whidbey.net/ohmsmath/webwork/javascript/decin2fr.html ">
> http://www2.whidbey.net/ohmsmath/webwork/javascript/decin2fr.html
> </a> This program is a walk-thorough which can also be done using a
> calculator on how to change decimal inches to 16ths (or some other
> selected denominator.)

<a
> href=" http://www2.whidbey.net/ohmsmath/webwork/javascript/denom.html ">
> http://www2.whidbey.net/ohmsmath/webwork/javascript/denom.html </a>
> allows students to investigate whether a fraction becomes a
> terminating or repeating decimal.

Neat!  The problem I see though is the advantage of staring at a computer screen
vs at a sheet of paper.  Students having great difficulty also have difficulty
seeing pattern.  I recall saying to one class, "All you see is x's and y's all
over the page."  They nodded in agreement.  The fact is that once the idea, the
pattern, the process, the algorithm is cemented, there is no need for a lot of
practice, and that a lot of practice does not necessarily cement the idea.  Some
of these exercises do show the process over and over, rather than regenerate
more problems and answers as do my spreadsheets, and I think that may be an
advantage.  It is sometimes difficult to determine when to stop and take another
approach though, if one is indeed possible, and especially within reasonable
time restrictions.

I've used this analogy before:  I can not draw, except rather poor stick images.
My sister-in-law is a consummate artist.  One day she saw a picture I had on
the wall, and told me what was wrong with it.  The point was I could not see
what she saw until she showed me [and she *was* right.]  Neither could I tell
such differences in any other painting afterwards.  She simply saw what I could
not.  It happens.  So what?  She had to ask me for the formula for the surface
area of a sphere.

I think that, if it is at all possible, the best way for those having trouble is
to assign situations where they need to apply the knowledge.  So, in how many
situations do students need to convert back and forth?  I'd suggest that they
look at converting metric to English [still used in the US] so that they can
work as readily with each.  One problem is the lack of type-questions in
todayts' texts. Lots of pretty pictures but few and meaningless problems.  I
just sent a late 1800s arithmetic text to a colleague/friend.  It had at least
2000 type problems to choose from in all sorts of situations.  This is what they
need in my opinion.  However, we need to get rid of the "drill and kill" stigma
offered by those who also spout that "those who can, do ...'  etc..

David.