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Website
National Council of Teachers of Mathematics

The Math Forum: Student Center

For Students 9th - 10th
The Math Forum Student Center provides math news, notes, challenges, and much more. Dr. Math is here with the answers to students' math questions. There's a teachers' section, a research division, and a parents' part. This site also...
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Website
Other

Mathematics Computation

For Teachers 3rd - 8th
This site gives you math worksheets to save the teacher time and keep the students learning.
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Website
University of Vienna (Austria)

University of Vienna: Maths Online

For Students 9th - 10th
The University of Vienna, Austria, created this site to help bring the worlds of math and technology together. You have access to many applets and downloads that allow you to create lessons, tests, and puzzles. There are also great...