When dynamic applets appeared, you finally could build up a reasoning and prevent that the board in the classroom became a mess.[br]Stepwise you could fill your board, even show a previous step without using a wiper.[br]"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.

You can add more features to the applet: a table of values, the calculation of a sepatate value etc...[br]Marvelous material voor 'What if'-questions.[br]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...[br]Just: Give the student some room to think for themselves and don't trow it all ont the table yourself at once.