Want to learn how to tackle those tough AMC/AIME/Olympiad algebra problems? Check out Art of Problem Solving's NEWIntermediate Algebra by Richard Rusczyk and Mathew Crawford. Over 1600 problems!
The diagram for 3-dimensional coordinate system is bad: the grey gridlines make it look like a 2-D coordinate system with the line drawn in. If those lines were erased, the diagram would be much clearer. --JBL 10:09, 4 January 2008 (EST)
Want to learn how to tackle those tough AMC/AIME/Olympiad counting and probability problems? Check out Art of Problem Solving's NEWIntermediate Counting & Probability by David Patrick.