Date: Dec 27, 2012 9:24 AM
Author: Richard Strausz
Subject: Re: A Point on Understanding

> On 15 Dec 2012, Robert hansen wrote:
>

> > One of his observations was that students will
> accept
> > that 0.333... is 1/3 but have trouble accepting
> that
> > 0.999... is 1.
>
> I wonder if "accepting" this would be a problem if
> these students had been taught how to convert a
> repeating decimal into a fraction, as we were when I
> was in high school?
>
> Let x=0.999...
> then 10x=9.999...
> then 9x=9
> and x=1


When I taught Algebra I, I would show students the method you cited. Many students reacted as if it were a trick - like when one 'proves' that 2 = 1 by using an illegal divide-by-zero step.

Richard