We have examined three kinds of reuse: application reuse, designing for reuse, and code reuse, which give mathlet developers and teachers the ability to leverage prior work to create new mathlets. The JOMA mathlets represent the cream of the crop of online mathematical activities, but even they have room for improvement to support reuse. We presented an assortment of techniques for mathlet developers to improve reusability. In the next article we'll go into depth on beans and interoperability.