A nice, well ordered board!

dynamic applets... the board of your classroom never was as clean...

When dynamic applets appeared, you finally could build up a reasoning and prevent that the board in the classroom became a mess. Stepwise you could fill your board, even show a previous step without using a wiper. "What if" became easy, because I can easily 'ride' on my graph, even without a toy car and change the equation whenever I want without spoiling the blackboard.

More features

You can add more features to the applet: a table of values, the calculation of a sepatate value etc... Marvelous material voor 'What if'-questions. With checkboxes you can control what's shown or hidden.
In a table you can study the limits of a function or the sign of a first degree function or the symmetry of a parabola... Just: Give the student some room to think for themselves and don't trow it all ont the table yourself at once.