## Vertex Form Grapher

This is an excellent introduction to the vertex form of a quadratic function.

http://www.heymath.com/main/samples/us21/teacherstemplate.html

## Applications of Quadratics - Zero Gravity

This web page isn't particularly interactive, but it is an excellent application of quadratic functions.

http://www.heymath.com/main/samples/us20/teacherstemplate.html

## Introduction to Simultaneous Equations

This is an excellent introduction to the topic of simultaneous equations.

http://www.heymath.com/main/samples/us19/teacherstemplate.html

## The Balance Method

This web page does a great job of introducing the balance method to solve equations.

http://www.heymath.com/main/samples/us18/teacherstemplate.html

## Coordinate Geometry

This is an interactive one quadrant number plane

And this is an interactive four quadrant number plane

## Archimedes' Bath

A fantastic implementation of the 'bath graph', ie the graph of water height vs time if a bath tap is turned on/off, and/or the plug is pulled out, and/or a person gets into/out of the bath. And a yellow duckie is included for free. Three thumbs up!

http://www.mathsonline.co.uk/nonmembers/gamesroom/sims/archi/archi4.html

## Correlation Demo

A Java applet in which students can change the number of points and the correlation coefficients, as well as add points. They can also show the regression line and the residual plot. Three thumbs up!
http://stat-www.berkeley.edu/~stark/Java/Html/Correlation.htm

## Variables, Expressions and Equations from HippoCampus

An interactive lesson by HippoCampus on variables, expressions and equations.
http://tinyurl.com/5zwjvc

All of the HippoCampus interactive lessons can be found at
http://www.hippocampus.org/

## Least Squares Regression Line Animated

Six points are shown along with a line that passes near them. The applet shows the square of the residual of each point as well as the sum of the squares. Your task is to change the gradient and y-intercept of the line to minimise the sum of the squares. Three thumbs up!