It's hard to believe it's all free! This trove of information from thefreedictionary.com offers all sorts of information on math. From algebra and integers to derivatives and polynomials, it's all here. By scrolling over or clicking on a link, the visitor is treated to a sometimes whopping amount of information about the given topic. For those simply interested in math, math lovers, or possibly a teacher who needs to venture into a rusty subject area before next fall, this site is well worth a look. Note: while it's free, there are some advertisements.