SAGE is a free, open-source computer algebra system. [more inside]
posted by kaibutsu on Oct 30, 2009 - 37 comments

MathTV is a real problem solver for many. It is also found on YouTube, and is free. Here is some background.
posted by Brian B. on Mar 21, 2009 - 8 comments

EducationFilter: California becomes the first state to mandate all 8th graders take Algebra; in part because U.S. students constantly trail their peers from other nations in mathematics. At least one person thinks it's a bad idea ("If only 25 percent of this nation ever earns a college degree, why insist that all children take algebra in eighth grade?"). Here's the algebra curriculum 8th graders will have to learn. [more inside]
posted by jabberjaw on Jul 10, 2008 - 124 comments

Accidental Astrophysicists: "They started with algebra and ended up learning about gravitational lensing (PDF)." [Via linkfilter]
posted by homunculus on Jun 17, 2008 - 22 comments

KnowHow2Go wants you to take on the tough classes - such as Biology, Foreign Languages, and Algebra II - to prepare yourself for college.
posted by divabat on May 26, 2008 - 31 comments

Logólogos makes mathematical equations out of the 'creative' process of logo design.
also a good example of "you don't need to speak the same language" blogging
posted by wendell on May 23, 2008 - 31 comments

Walter Randelshofer's Pretty Patterns collection (for Rubik's cubes up to 5x5x5) is one of the nicest twisty puzzle sites going. It's based on his CubeTwister software, which you can download (including a lovely OS X standalone). If you really want a treasure trove of twisty polyhedra, check out gelatinBrain's enormous collection of java applets (which unfortunately don't do so well on macs). Are those things even physically possible? Really? Mini bonus: Randelshofer also hosts an archive of fondly-remembered Amiga animations.
posted by Wolfdog on Mar 31, 2008 - 8 comments

Interactive mathematics miscellany and puzzles, including 75 proofs of the Pythagorean Theorem, an interactive column using Java applets, and eye-opening demonstrations. (Actually, much more.)
posted by parudox on Dec 1, 2007 - 11 comments

The Klein Four is a group of math students at the Northwestern University who delight in bringing you various lovely, well-sung A Capella songs infused with their very own and very nerdy flavour. They're not the newest of the web, having released their first CD in 2005, but witty lyrics and five-part harmonizing are definitely worth checking out. I did do a search for this and didn't find anything. Please don't kill me.
posted by Phire on May 23, 2007 - 14 comments

The Value of Algebra: "Gabriela, sooner or later someone's going to tell you that algebra teaches reasoning. This is a lie propagated by, among others, algebra teachers."
posted by daksya on Feb 16, 2006 - 190 comments