"Free tutorials using java applets to explore, interactively, important topics in precalculus such as quadratic, rational, exponential, logarithmic, trigonometric, polynomial, absolute value functions and their graphs. Equations of lines, circles, ellipses, hyperbolas and parabolas are also explored interactively. Graph shifting, scaling and reflection are also included. The definition and properties of inverse functions are thoroughly investigated. A graphical approach to 2 by 2 systems of equations is included. "
A huge collection of maths videos on a wide range of topics. A super resource for older students, but even better to use to brush up on your own maths and teach the lesson yourself.