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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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Discovery Education

Discovery Education: Web Math: Algebra

For Students 9th - 10th
This WebMath site provides links to tutorials and lessons in both Algebra I and II. Links to topics such as factoring, solving equations, polynomials, simplifying equations, graphing, and much more.
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PBS

Pbs Learning Media: Pizza Toppings

For Students 6th - 8th Standards
This Cyberchase video features Bianca who uses Venn Diagrams to make a pizza that satisfies the topping preferences of her friends.
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Ducksters

Ducksters: Kids Math: Simplifying and Reducing Fractions

For Students 3rd - 8th Standards
Understand the steps to do when simplifying and reducing fractions including finding the greatest common factor on this website.
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Discovery Education

Discovery Education: Web Math: General Math

For Students 3rd - 8th
An extraordinary site that will help you with your math homework. Presented in a format that is both easy to understand and educational. Navigate through numerous instant-answer, self-help math solvers to help you figure out your math...