Half, quarter, sixth, eighth - all of that makes sense when cutting a pie or a cake or a loaf of bread.
It becomes unworkable when dealing with "3 yd 1 ft 8-5/32 in" plus "1 yd 2 ft 3-11/16 in" as opposed to "3255 mm + 1618 mm = 4873 mm".
Carleton
-------------- Original message --------------
> Fractions have to be taught as they are commonly used in day to day life (in
> a less than mathematical way).
>
> The old "pizza argument" could be used - ie to visualise cutting it up in to
> quarters or eighths. One can't expect a kid to only recognise a pizza cut
> into 10 pieces to make sense of the words that describe what that looks
> like.
>
> Plus manipulation of fractional arithmentic taxes the mind in a healthy way
> as part of education.
>
> Incidentally - My weakest skill at school was fractions - I would have LOVED
> for them not to be taught when I was at school ;-)
>
>
> >From: "Philip S Hall" <[EMAIL PROTECTED]>
> >Reply-To: [EMAIL PROTECTED]
> >To: "U.S. Metric Association" <[EMAIL PROTECTED] E.EDU>
> >Subject: [USMA:34807] Re: fractions
> >Date: Tue, 11 Oct 2005 19:50:39 +0100
> >
> >>Without rounding, 1/3 becomes 0.3333333333333 and 1/7 becomes 0.142857142.
> >>
> >>What's wrong with 0.33 or 33% or 0.14? Accurate enough for most people's
> >>needs.
> >
> >I don't think we're on the same wavelength here or maybe we're at cross
> >purposes.
> >
> >I'm perfectly happy with the idea that decimal form is better for
> >measurment. With decimal we can round measurements or express them to any
> >degree of accuracy we like with an appropriate choice for the number of
> >significat digits and the last digt for rounding. That reflects the nature
> >of measurement itself. All measurements are an approximation to varying
> >degrees. Decimal notation lends itself to that perfectly.
> >!
> >What concerns me is the suggestion that somehow ! fraction s (of the form x/y)
> >can be surgically removed from the mathematics curriculum. I don't
> >understand how you can talk about tenths and hundredths etc, in isolation
> >from the general concept of an nth of something! For example 0.237 is just
> >code for 237/1000 They are closely related and inseparable.
> >
> >Now I realise that some of you are merely saying that it is a waste of time
> >learning to do arithmetic with x/y type fractions because nobody uses them
> >in practice, except maybe to cope with measurement units where you end up
> >with awkward fractions.
> >
> >Well I think there is more to it than that. Even without non-decimal
> >measurement systems it would still be quite important for kids to learn the
> >principles. But in order to teach it you need a means of assessment. That
> >can only be done by exercises that will i! nevitably involve a certain amount
> >of doing arithmetic.
> >
> >There is also the point that time isn't decimal nor is angular measurement
> >in degrees.
> >
> >It's all too easy for the likes of us as adults who take for granted what
> >we know about fractions and are able to instincitively apply them to the
> >idea of a half or a quarter or a two thirds of something. We are able to do
> >this because we have benefitted from a rounded education in basic
> >mathematics. We musn't try to deprive future generations of this. It's not
> >part of the deal where metrication is concerned.
> >
> >Phil Hall
> >
>
