Well-sorted tools with brief descriptions. Great for introducing newbies to the subject, but experienced people will like the summary, as well.

Wiki-answers site for family and club math Q&A

I wish we could add tags to other people's items without overwriting their authorship!

Steven, you shared a link and I wanted to add a tag to it. However, Diigo does not have a separate "add tag" function. The only way to add a new tag is to share the same link to the group, again. However, it overrides the author - now the link says "Shared by Maria Droujkova" even though you linked it first. I hope it makes sense. We discussed it with Darren when I first started to use Diigo Groups: http://groups.diigo.com/group/math-links/content/can-you-add-tags-to-other-people-s-bookmarks-959243

The boundaries of human presence on Earth. Also, how long it takes you to boil an egg at the top of Everest. Good to know!

An excellent overview of GeoGebra compass and straightedge construction

Evaluation of OLPC programs globally: a literature review

We need a simple way to communicate math on the Web. I'm often amazed that a really popular math forum like Ask Dr Math has these tedious math typing suggestions where you have to enter hundreds of spaces to get things to line up.

Who created mathematics? Where did it begin? To answer these questions, we need to think about what mathematics is. In their work on ethnomathematics, Borba (1990) and D'Ambrosio (1990) define the compnonents of ethnomathematics as the follows: ethnos - within a cultural environment mathema - explaining and understanding in order to transcend, managing and coping with reality in order to survive and thrive. tics - techniques such as counting, ordering, sorting, measuring, weighing, ciphering, classifying, ordering, inferring and modeling.

Beyond simple math and grouping (like "(x+2)(x-4)"), there are some functions you can use as well. Look below to see them all. They are mostly standard functions written as you might expect. You can also use "pi" and "e" as their respective constants.

This looks very beautiful!