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Activity
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Fibonacci Sequence

For Students 9th - 10th
This site from the Math Forum explains the explicit formula for fibonacci numbers.
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Website
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Degrees in a Circle

For Students 9th - 10th
Dr. Math answers a students question as to why a circle contains 360 degrees.
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Activity
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Irrational Powers

For Students 9th - 10th Standards
Math Forum response considering whether an irrational number taken to an irrational power yields a rational or irrational number. Responses include a method of generating irrational #s x & y such that x^y is rational.
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Activity
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Rational and Irrational Number

For Students 9th - 10th Standards
Math Forum response to the size of the set of rational numbers. Responses investigate the countability of sets and basic set theory.
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Activity
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Rational Numbers

For Students 9th - 10th Standards
Math Forum response addressing how many elements are in the set of rational numbers. Responses investigate the countability of sets, and how sets with an infinite number of elements can be counted and compared to other "infinite sets."
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Activity
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Rational / Irrational Numbers

For Students 9th - 10th Standards
Math Forum response providing methods to prove that between any two numbers there exist a rational and an irrational number.
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Activity
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Counting Rationals and Integer

For Students 9th - 10th Standards
Math Forum response providing a proof that there are as many rational numbers as integers.
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Activity
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Definitions of Rational, Irrational

For Students 9th - 10th Standards
Math Forum definition and explanation of rational and irrational numbers, the definitions of mathematics is also addressed.
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Activity
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Irrational Pi

For Students 9th - 10th Standards
Math Forum response to the question of why pi is not rational if it is a ratio of circumference to diameter.
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Activity
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: About Rational Numbers

For Students 9th - 10th Standards
Math Forum response giving a rather thorough overview of rational and irrational numbers, with a brief look at the history of these and other number sets.
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Activity
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Square Roots and Irrational Numbers

For Students 9th - 10th Standards
Math Forum response to whether square roots of all non-perfect squares are irrational. Contains a proof showing that such cases are, indeed, irrational.
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Activity
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Irrational Numbers; Rational Square Roots

For Students 9th - 10th Standards
Dr. Math responds to how one can tell whether a number is rational or irrational. A proof is discussed in the response.
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Activity
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Domain and Range

For Students 9th - 10th
This page from the Math Forum contains a question and answer session on how to find range in rational functions. Example problem is given.
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Activity
National Council of Teachers of Mathematics

The Math Forum: Learning to Factor

For Students 9th - 10th
Math Forum Faq which briefly defines greatest common factor and links to an in-depth investigation of how the GCF is found.
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Activity
National Council of Teachers of Mathematics

The Math Forum: Finding the Greatest Common Factor of Two Numbers

For Students 9th - 10th
Math Forum response to question about finding the greatest common factor by using the factoring tree method.
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Website
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Formula for Greatest Common Divisor.

For Students 9th - 10th
This site is a question and response to a student asking Dr. Math about the greatest common divisor, he gives an interesting way to find the gcd, as well as the button on calculators which commonly does the math for you.
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Activity
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Greatest Common Factors, Least Common Multiples

For Students 9th - 10th
Math Forum response to request for info on how to find greatest common factors, and how this compares to least common multiples. Explanation includes examples of each.
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Activity
National Council of Teachers of Mathematics

The Math Forum: Rotational Symmetry

For Teachers K - 1st
This is a good site for elementary teachers to help educate students about symmetry by using pattern blocks. This link has multiple activities that the instructor could use including technological and standard activities.
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Website
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: What Is a Ratio?

For Students 3rd - 8th Standards
The question posed to Dr. Math is, "What is a ratio and how do you do it?" Dr. Math breaks it down in this detailed explanation using real world scenarios.
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Activity
National Council of Teachers of Mathematics

The Math Forum: Calculating Sales Tax

For Students 3rd - 8th Standards
Dr. Math is asked about calculating sales tax. A quick and easy to follow explanation of how it works using fractions, decimals, ratio, and percent.
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Website
National Council of Teachers of Mathematics

The Math Forum: Geometry: Introduction for Primary Students

For Teachers 3rd - 5th
These lessons are designed to guide young children through an introduction to geometry. Children learn to recognize shapes and to create patterns, and explore spatial relations and symmetry. Each activity is aligned to mandated standards.
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Lesson Plan
National Council of Teachers of Mathematics

The Math Forum: Lesson Plan: Measurement, "Inch by Inch"

For Teachers 1st - 3rd Standards
This is a great measurement lesson plan with a literature connection, "Inch by Inch" by Leo Lioni. It uses a variety of activities where students use the inch unit.
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Activity
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Inequalities

For Students 9th - 10th Standards
"Dr. Math" responds to a student question about solving inequalities. Within the response, a list of the properties of inequalities is provided. Site by Math Forum
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Activity
National Council of Teachers of Mathematics

The Math Forum: Analytic Geometry Formulas

For Students 9th - 10th Standards
This site from The Math Forum defines and explains, with examples, analytic geometry. Content includes a focus on one, two, and three dimension analytic geometry. Links are also provided for additional information.