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### Teaching Elementary Concepts

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Date: 04/04/97 at 21:53:22
From: lisa
Subject: 3 different approaches

1. I need to develop a meaningful understanding and skill in order to
teach rational counting...how do I effectively teach  rational

2. Develop an understanding of "prime" and "composite" numbers. How
can I teach this concept to fourth graders?

3. Illustrate that the square root of 2 is an irrational number. How
can I illustrate this to eighth graders?

I need this information as soon as possible

Thank you so much!
```

```
Date: 04/05/97 at 18:02:46
From: Doctor Judy
Subject: Re: 3 different approaches

You have asked three very good questions.  I'll try to point you to

1. To learn rational counting, 1st grade students should be given
opportunities to group, sort and count using favorite objects.
Literature should also be connected to math by reading counting books
with the students.  For titles, check:

http://www.luc.edu/schools/education/csimath/zbib.htm

2. For Prime and Composite number understanding I suggest the Sieve
of Eratosthenes.  You can find directions and information at:

http://mathforum.org/dr.math/faq/faq.prime.num.html

When students actually generate the prime numbers using this method it
helps to reinforce the concept that composites have more than two
factors.

3. For the square root of 2 you might try to have the students "find,"
by guessing, the exact number that when multiplied by itself is equal
to 2. Students would try to solve x^2 = 2. Directions for finding
square roots without a calculator are at:

http://mathforum.org/dr.math/faq/faq.sqrt.by.hand.html

For an explanation of rational vs. irrational numbers, search the Dr.
Math Archives.

I hope that these ideas will be helpful to you

-Doctor Judy,  The Math Forum
Check out our web site!  http://mathforum.org/dr.math/
```
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