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

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 Rex Boggs Posts: 12 Registered: 12/6/04
re: el fractions etc
Posted: Aug 10, 1995 8:05 AM

>I would like to be able to come up with a concrete 'materials'
>model of what is occurring. (I don't have one presently)
>

> >1/4 is 5/12 of 3/5. I pulled this from Ted's post and tried to
>demonstrate this with tiles, but I was not able to it. Can you help me?

Well here is one way to represent this concretely.

Start with a strip of paper 20 cm long, ruled every 1 cm, as follows...
________
| | |
| | | etc, (this diagram shows the first 2 cm of the strip)
| | |
________

Colour in 1/4 of the strip, starting at the left. You will colour in 5 of
the rectangles.

Cut off 3/5 of the strip, from the left, ie, 12 of the rectangles. Of those
12 rectangles, 5 are coloured in.

So 1/4 (of the whole strip) is 5/12 of 3/5 (of the whole strip).

BTW, I appreciated how Ted put these problems into a context. If my goal is
to mark 3/5 of my exam papers today, and I've already marked 1/4 of them,
why, I'm 5/12 of the way there!

Cheers

Rex

Rex Boggs | High above the hushed crowd,
rex@cq-pan.cqu.edu.au | Rex tried to remain focused.
| Still, he couldn't shake one
Glenmore High School | nagging thought: He was an
Rockhampton, Quensland | old dog and this was a new
Australia | trick - Gary Larson