From: Loyd <loydlin@aol.com>
To: Teacher2Teacher Public Discussion
Date: 2004091920:58:50
Subject: Unit cost.

My father, who only had an eighth grade education plus a little time
at a normal school for teachers, was always asking us questions at the
dinner table.  One which helped me quite a bit at an early age: If
eggs are 12 cents per dozen, how much does one egg cost?  He taught us
to find the price for one item and then it was easy to find the cost
for 20 or any number.  Of course you can use ratio and proportion and
then it is a little easier to find the cost of odd amounts such as: If
eggs cost 31 cents per dozen, how much does 72 eggs cost?  Using ratio
and proportion, it is just 31 is to 12 as x is to 72.  Or, 31/12=x/72.


Or you can find the cost for one and then multiply by 72 to find the
cost for 72.  I think simple problems like this are important for
young children to learn.  It is a simple thing to do once you learn
the process.  

If your students haven't had ratio and proportion yet, you can still
give them simple problems that helps them find the unit cost.

Now here is a little simple brain teaser you can use:

Answer Quickly:  "How many 3-cent stamps in a dozen?"  Often the
answer is four, but of course it is 12.  When I first heard that
problem, 3 cent stamps were all that was required for first class
mail.  

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