This applet and accompanying activities illustrate the formal definition of continuity of a function at a point through a series of interactive exercises.
Open the pdf file and applet in separate windows (or print the pdf file instead) so you can work through the suggested activities.
Click here to download all five LaTeX activity files as a single compressed file. These have the same content as the posted pdf files. They are included in LaTeX form for those who would like to edit them for their own use.