Teaching function notation F(x), input and output machine. Drag an input into the animated machine, and drag an output out! Have students find an equation of the output when you put "x" into the machine. The output can be found hidden in the machine (move curser over the blue gear and drag the hidden object out). the "Input" objects are also layered in certain fashion so that you can visually put something into "F(___)" (For example, drag a 2 so that it is in between the parenthesis of "F(___)"). You can also reverse the process by seeing the output first, and have students find the input algebraically.