GeoGebra is a free software program for mathematics instruction and would be a great resource for any algebra, geometry, statistics, or calculus classroom. The interface is divided into three sections, including an input bar for equations and functions, an algebra view to see and edit equations and functions, and a graphic view that will allow the teacher/student to construct objects and see the graphs of functions. The construction tools for this software are vast and include options such as: lines through points, bisectors, tangents, locus, intersections, polygons, compasses, circular arcs, ellipse, hyperbole, area, slope, and the list goes on. Teachers and students can use this software to draw graphs, transform graphs, construct parallelograms, find mean, median, and mode, construct a tangent, and much more. If needed, teachers and students can save a GeoGebra document as a ggb (GeoGebra file), gif, png, or your file can be printed. In addition, you can export as a "Dynamic Worksheet as Webpage (HTML)" to easily share the file by email or link to your website.
The GeoGebra software can be downloaded to your computer at the GeoGebra website or you can run a fully functional applet in your web browser. If you run the applet version, you will have to allow the Java plug-in to run on your computer. In addition, the GeoGebra website houses a Materials section, including interactive worksheets, collections, and tutorials.
Classroom Integration Resources:
The links below will provide resources to get you started as well as classroom lessons/resources.
7 Steps to Interactive Math with Geogebra: The Basics - This blog post is a great resource to help get started with GeoGebra. The author also has a section of his Broken Airplane blog devoted to GeoGebra resources.
GeoGebra in 10 Lessons - This is a link to a pdf which includes an overview of the GeoGebra interface, menus, and tools, as well as 10 lessons you can use for your classroom.
GeoGebra Math Interactive Lessons - These teacher tools are organized by content and skill. This resource continues to grow and the current worksheets are wonderful.