2 March 1998 Vol. 3, No. 9
THE MATH FORUM INTERNET NEWS
Math Parent Handbook  MathWorld Interactive  Integer Pairs
MATH PARENT HANDBOOK  GRADES K6
A Guide to Helping Your Child Understand Mathematics
http://www.eduplace.com/math/res/parentbk/
An introduction to contemporary math, including technology
in the classroom, with teaching strategies to help children
become mathematical thinkers; resources and ideas for working
with your child; quick and easy math games (no special
equipment is needed); math activities for when you're out
and about at the grocery store, in restaurants, or shopping;
"refrigerator math" (games that can be posted on the fridge
for the whole family to participate in); and a list of books
for grades K2 and 36 to read with your children.
This guide was developed for parents of children using the
Houghton Mifflin mathematics program, but almost all of the
information presented can be used by anyone wanting to
explore mathematics with a child.
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MATHWORLD INTERACTIVE  Carolynn S. Mortensen
Breakfast cereal usually comes with the weight listed
on the box. Sometimes when you open the box it does not
seem full to the top. Do you think you have been cheated?
Can you explain why the box is not full but there is
still the correct weight of cereal? Is weight a good way
to sell cereal? Is there a better way?
Participating students from all over the world work on this
and other MathWorld Interactive Challenges, openended
word problems at four levels:
Grades K3 (ages 58)
http://www.mathworldinteractive.com/exk3two.html
Grades 46 (ages 911)
http://www.mathworldinteractive.com/ex46two.html
Grades 78 (ages 1214)
http://www.mathworldinteractive.com/ex78two.html
Grades 912 (ages 14+)
http://www.mathworldinteractive.com/ex912two.html
Challenges are issued every nine weeks and students are
asked to follow a specific format:
 write what you know about the problem (the facts)
 write what you are looking for (the questions)
 write all your problemsolving strategies
 write your solutions (the answers)
 explain how you checked your work
 extend the problem by writing a new problem based on
the original
Participants use an online form or the MathWorld Interactive
Message Boards to submit their solutions. Students receive
email awards highlighting their strengths and achievements,
and the results are also posted online in the MathWorld
Interactive Hall of Fame. Find these areas and others at:
http://www.mathworldinteractive.com/
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DUMB LUCK... AND INTEGER PAIRS  geometrypuzzles
http://mathforum.org/epigone/geometrypuzzles/vimppleldquax/
http://mathforum.org/epigone/geometrypuzzles/smalzhiphal/
A recent conversation on the newsgroup geometrypuzzles,
which began with an investigation of how to derive an
equation for the radius of the circle that will circumscribe
a general triangle of sides a, b, and c.
Monte Evans found two triangles with sides 10,11,12 and
10,7,4 that could both be circumscribed by a circle with
radius 40/sqrt(39), and asked, "Does anyone know of any
other pair of triangles, each side being an integer, that
is circumscribed by one circle?"
After many interesting posts, Evans commented:
... To John Conway, Pat Ballew, Helena Verrill, and
Don Gilmore  Many thanks for the interest shown in
this problem! I am rapidly learning that my amazing
coincidence wasn't quite as unusual as I thought.
Pat and his energetic students jumped right on this
problem and came up with 3 pairs of such triangles, and
John Conway came up with a triple! If I correctly
understand Conway's last entry, we can have a circle with
as many integersided triangles in it as we desire. It
may be a rather large circle, by the time the rescaling
is through. My request for an analytical approach has been
answered in spades! WOW...
To find all the relevant threads, use the searcher to look for
the words integer triangle :
http://mathforum.org/discussions/episearch/geom.puzzles.html
For more about geometrypuzzles, including how to join, see:
http://mathforum.org/discussions/about/geometrypuzzles.html
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Join the Math Forum http://mathforum.org/join.forum.html
Send comments to the Math Forum Internet Newsletter editors
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