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Topic: el fractions etc
Replies: 14   Last Post: Aug 10, 1995 8:05 AM

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Norm Krumpe

Posts: 53
Registered: 12/6/04
re: el fractions etc
Posted: Aug 9, 1995 1:45 PM
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>If I am thinking about this correctly then 1/4 divided by 3/5 can be
>restated as 3/5 is 1/4 of what? So if you re-build the rectangle so that
>original 3/5 is now 1/4, the resulting rectangle is indeed 12/12, but here
>I am stuck. If the tiles with x's were red and I build the rectangle I
>still have only 3 red tiles or 3/12.
>
>What am I doing wrong?
>
>Looking forward to hearing from you:-)
>
>Eileen
>


Shouldn't 1/4 divided by 3/5 be restated as "1/4 is 3/5 of what"?
Similarly, 8 divided by 2 could be restated as "8 is 2 of what?"

So, if 1/4 is 3/5 of "something", I would break 1/4 into three equal
sections, so that each section would represent 1/5 of "something." But,
breaking 1/4 into three equal sections results in sections that are 1/12.
So, 3/12 is 3/5 of "something". So one twelfth is one fifth of "something".
So, to find the whole "something", I would need two more fifths of
"something" which would be two more twelfths added on to the three twelfths,
giving me 5/12.

Whew!



Maybe I can show this using line segments:

--------- = 1/4, which is 3/5 of "something".

--- --- --- = 3/12, which is 3/5 of "something".

--- --- --- --- --- = 5/12 which is 5/5 of "something".

So, --- --- --- --- --- = 5/12 = "something."

So, --------------- = "something".


Norm Krumpe







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