• Algebra Balance Scales---Negative
Linear equations are presented on a two pan balance with variables on each side. The user can solve equations in the same way as described in the text. The Negative version uses balloons for negative values and negative variables.

• Cool Math
This section of the Cool Math website is designed for teachers and does include a sample lesson on functions. Teachers can register to this site, at no charge, and can then gain access to more teacher resources on functions.

• Elementary lesson plans
This site, published by Apple Learning Exchange, contains elementary lesson plans for many content areas. Within the math section, there are several lesson plans including algebraic topics for grades 2 and up. The lesson plans sometimes include links to interactive sites for practice.

• Function Machine
A function machine is shown with a secret rule. Numbers are dragged and dropped into the machine, and the output is recorded in a table. The goal is to determine the function rule. A very good example of many function machine applets you might find.

• Funschool.com
The Funschool website contains mathematical games on number concepts and operations, fractions, decimals, percents, geometry, probability, patterns and equations.

• goENC
The Eisenhower National Clearinghouse site offers activities and lessons to address algebraic thinking and equations.

• Graph Sketcher
Works very much like a graphing calculator for graphing functions of any type. A good demonstration tool for making graphs of equations.

• Growing patterns
This site is a simple, yet very entertaining, example to show the youngest of students how growing patterns work. The students would enjoy watching the "seeds" grow over and over again and would experience a representation of what a growing pattern looks like.

• Learning About Rate of Change
A nice interactive lesson in which the cost per minute to make a phone call (the slope) can be adjusted and then the graph of the cost can be displayed. A slider helps connect points on the two graphs.

• Pan Balance---Shapes
With each problem, four shapes are assigned unknown values. By stacking shapes on the two balance pans, the user attempts to balance the scale and then create additional balances. A numbers version and an expressions version are extensions of this applet.

• PurpleMath.com
An excellent resource for reinforcing algebraic thinking, from elementary to high school. Each topic has thorough background notes with interactive features. All topics include examples worked out on the page, along with practice opportunities for students.

• Slope Slider
A good interactive tool for illustrating the meaning of slope and the y-intercept for a linear equation of the form y = mx + b. The user can use a slider to change the value of m or b and see the graph change dynamically.

• Teaching functions
This Project Interactivate site contains a list of activities relating to teaching functions. The activities include a very basic introduction to functions, as well as teaching linear functions, graphing and functions, and others. All activities relate the NCTM standards to the objectives being taught.

• Understanding Distance, Speed, and Time Relationships Using Simulation Software
The speed and starting position of two runners can be set. Runners can even go in opposite directions. Graphs of each runner are created dynamically as the runners are set in motion.

• Video-based courses
This page describes video-based courses available for teaching algebra and functions to middle school students. The courses can provide the teacher with graduate course credits.