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!

http://www.dynamicgeometry.com/JavaSketchpad/Gallery/Other_Explorations_...

Below are two TI-Nspire documents from Spencer Williams that show visually the operations of adding and subtracting fractions. There is also a pdf file to support the use of these in the classroom. Thanks, Spencer, for sharing these.

Take a starting number and apply a set of instructions to it to achieve a finishing number.

Click create to generate a new start number and instructions. The start number will not appear. You can choose whether to show the start number or the answer. Showing the answer modifies the puzzle so that students have to do the inverse of the instructions to find the start number.

A timer can be applied. The length of time available for each instruction can be adjusted. When the length of time has passed a light appears below the instruction to show the students that they should move on.

Instructions
http://www.teacherled.com/2008/08/31/follow-on-maths/

Resource
http://www.teacherled.com/resources/followon/followonload.html

This interactive resource is useful for demonstrating the volume of cubes and cuboids.

Instructions
http://www.teacherled.com/2008/09/09/cuboid-exploder/

Resource
http://www.teacherled.com/resources/cuboidexplode/cuboidexplodeload.html

A neat visual way to find the LCM (lowest common multiple) of two numbers.

http://www.teacherled.com/resources/LCM/LCMload.html

(1) Confidence intervals on the mean are generated for simulated experiments. The confidence level and sample size can be altered. Note that the website currently doesn't work with Netscape/Mozilla 4.0 or higher.
http://www.ruf.rice.edu/~lane/stat_sim/index.html

(2) This applet simulates finding confidence intervals for the mean of a normal random variable. A sample of size 20 is generated from a standard normal random variable.
http://www.math.csusb.edu/faculty/stanton/m262/confidence_means/confiden...

(3) This applet is similar to (2) above, except it repeats the process a chosen number of times
http://socr.ucla.edu/htmls/exp/Confidence_Interval_Experiment.html

And here are some notes/instructions for this applet
http://wiki.stat.ucla.edu/socr/index.php/SOCR_EduMaterials_Activities_Co...

This applet estimates and plots the sampling distribution of various statistics. You specify the population distribution, sample size, and statistic. An animated sample from the population is shown and the statistic is plotted. This can be repeated to estimate the sampling distribution.

http://www.ruf.rice.edu/~lane/stat_sim/sampling_dist/index.html

If you need to display a working scientific calculator to the whole class, look no further.

http://www.ecalc.com/calculator/scientific?ca=BCALC&typ=MIO&src=USB&vrs=...

You can also download a free virtual four-function calculator that can be carried with you, eg on a memory stick.

http://www.ecalc.com/files/mio/ecalc/basic/usb/calculator.exe

Add some points to the scatterplot. The applet will calculate the correlation coefficient and the sum of squares. You can also choose to show the least-squares regression line and the x-mean and y-mean lines. Very instructive!

http://bcs.whfreeman.com/yates2e/pages/bcs-main.asp?v=category&s=00020&n...

This is a great little interactive activity. Four scatterplots are displayed along with four correlations. Match them!

http://www.stat.uiuc.edu/courses/stat100/java/GCApplet/GCAppletFrame.htm...