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Q&A #6998

Teachers' Lounge Discussion: Rational and irrational numbers

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From: Loyd <Loydlin@aol.com>
To: Teacher2Teacher Public Discussion
Date: 2007013113:00:44
Subject: Re: rational numbers

On 2007012813:51:36, Mark Freathy wrote:
>	
>why are percents not listed in textbooks as rational numbers?
>
>Can you place 30% on a numberline?
>
>Is a percent a number?
>

A rational number is a number that can be expressed as a fraction such
as 1/4.  30 % can be expressed as 30/100 so it is a rational number.  

All whole numbers are fractions but we usually don't write the
denominator.  For example, 2 can be written as 2/1.  

As far as number lines go, we we most often use whole numbers.  You
could never write all the fractions because between any two rational
numbers is another rational number.  

For example, a fraction (rational number) between 1/4 and 1/5 is
(1/4+1/5)/2
That is equal to (5/20 + 4/20)/2 or (9/20)/2= 9/40.  We could go on
for ever and ever.  

Hope this helps

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