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Topic: back to fractions - 9/13
Replies: 4   Last Post: Oct 1, 2013 3:10 PM

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Bill Marsh

Posts: 349
From: Port Angeles, WA
Registered: 12/22/08
Re: back to fractions - 9/13
Posted: Oct 1, 2013 3:10 PM
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Alain,


I really liked 'As engineers used to be fond of saying, the *real*
real numbers are the decimal numbers.'


I also liked what you said about ordering fractions. I recently wrote
the following.


Bill


Deciding which of two numbers is bigger is much easier with decimals
than with fractions. Decimal order is essentially alphabetical order,
and the Common Core State Standards want children to be able to look
up words in dictionaries in second grade. No second grader could
figure out which of 63/68 and 88/95 is the larger. Doing it by hand
the old fashioned way would require two multiplications, 63x95 = 5985
and 88x68 = 5984, then deciding that 5985 > 5984, so that 63/68 >
88/95. Not many second graders could do all this.


But most second graders could do what any sane adult would do: use a
calculator to find out that 63/68 = .9264705 and 88/95 = .9263157.
Deciding which of these is the larger is no harder than deciding which
of ?batting? and batch? comes first in the dictionary. Calculators
don't need to have keys for telling which of two decimals is larger.


On Tue, Oct 1, 2013 at 10:59 AM, Alain Schremmer
<schremmer.alain@gmail.com> wrote:
>
> On Sep 30, 2013, at 11:15 PM, Alain Schremmer wrote:
>

>> while it is not immediately obvious which of 718/439 and 642/417 WHILE it
>> is a lot simpler to decide which of 1.63553531 and 1.53956835 is.

>
>
> I meant
>
> while it is not immediately obvious which of 718/439 and 642/417 IS
> SMALLER, it is a lot simpler to decide which of 1.63553531 and 1.53956835
> is.
>
> Apologetic regards
>
> --schremmer
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