Why Divide Fractions?

Date: Sat, 5 Nov 94 17:33:44 PST
From: James Oliver
Subject: Dividing Fractions

Ok Doc, explain this so a random abstract counsellor (Cdn Spelling) type
can understand.

Where, in this wide world of ours, would one divide fractions.  For example:

3 2/5 / 7/8.  Can you give me a real life example.

Take care

James Oliver                               Admin for:
District Area Counsellor                   Chetwynd Connection
School District #59 (Peace River South)    First Class BBS
Chetwynd, BC                               Data  604 788-3918

From: Dr. Ken
Date: Mon, 7 Nov 1994 11:41:35 -0500 (EST)

James!

Well, if your real life is like mine, and you're a math major, they arise
all the time!  But let's say you're not a math major, just a regular old
citizen.  Sure, they come up.

Let's say you have three quarters of a pizza and four people walk in to your
room and say, "hey, can I have two fifths of a pizza?"  You either freak out
and say "no!", or you divide 3/4 by 2/5 and see if it's bigger than four.
So you get 

                  3/4    3 x 5   15
                  ___  = _____ = __ = 1  7/8
                  2/5    4 x 2    8

So there isn't enough pizza for all four people to get as much as they want.

Another example:  Let's say you have 5/3 acres (or 1 2/3 acres) of land in
the country, and zoning requirements are such that you have to have at least
one-third of an acre to put a septic tank in.  How many subplots can you
divide your land into to satisfy the requirement?

-Ken "Dr." Math


X-Sender: steve@mathforum.org (Stephen Weimar)
Date: Tue, 8 Nov 1994 09:54:44 -0500

James, I also find as I'm doing carpentry and construction that there many
times when I want to evenly space several objects along a length with
non-integer dimensions or figure out how many of a fractional something I
can cut out of a non-integer piece of lumber.  There are many ways to get
close enough, but sometimes it helps to know how to get a better answer.

-- steve

Date: Wed, 9 Nov 94 14:42:03 PST
From: James Oliver
Subject: Re: Dividing Fractions

>Let's say you have three quarters of a pizza...

Hi Ken,

Good example, I think I'll share that with my grade 6-7 students when I am
wandering through their room.  Never had trouble dividing fractions but
never had a firm grasp on what was happening.

Take care

James Oliver                               Admin for:
District Area Counsellor                   Chetwynd Connection