ALAN SELBY's mathematics appetizers range over arithmetic review problems, notions of what variables are, skills leading to algebra, painless theorem proving, complex numbers with some trig, the importance of slope (some calculus), a decimal perspective of error control and continuity (more calculus), and renaming the greater than sign (back to algebra).
Advice on how to read, how to learn, why go to school, etc. is included. The tone is sometimes funny, and the writing is dense, rich, and intriguing. There are reflections on teaching, so these materials can be used in the classroom and as a place for teachers to learn.
Alan's explanations of mathematical concepts using words and stories are particularly strong. Don't miss his Appetizers and Lessons for Logic, also on this site.
Key Curriculum Press has provided us with sample pages from _Introducing Dynamic Algebra with NuCalc_, a book by Tim Erickson that draws from a wide range of math topics and explains how to use NuCalc in solving traditional and not-so-traditional high school math problems.
You can access NuCalc files from the Web by downloading the NuCalc Web Helper application and configuring it as a helper application in your browser (instructions are included). These sample pages offer exercises to work through on transformations and the Fourier series.
The book and software are available from Key Curriculum Press. If you have a Power Macintosh, you have the software already: it comes free on those machines, where it's called "Graphing Calculator."
To find your particular interest, use the Search nctm-l link at the top right of the Archives page. Experiment by searching for the word "proof" (just the word, without the quotes) to find discussions of all kinds about the merits of proofs in Geometry - or look through the first thread that's returned by this search, 'Useful Problems', to get a feel for the depth and richness of the NCTM-L archive.
The Forum's page of Public Discussions offers many more searchable math archives: