Mathematica demonstrations covering almost every aspect of high school algebra and geometry needed for the study of calculus. Click the "Mathematics" link, then click "School Mathematics," "Algebra," and "Geometry" to view subtopics and, finally, selections. Each demonstration consists of a short interactive graphical illustration of a concept or problem. Although demonstrations are created by various authors, most are clear, concise, and effective. Warning: Not all demonstrations displayed will be accessible to precalculus or even calculus students; some will be more advanced (but very interesting!) Demonstrations can be viewed using Mathematica or the free Mathematica Player, which can be downloaded from the Wolfram Demonstrations Project website.