To improve understanding of identities and inverses, and to provide a stronger foundation for future mathematics, Sandra Miles designed a two-part lesson that makes the relationship between identities and inverses explicit. This article illustrates Miles' teaching of the first part of the lesson, focused on addition and subtraction, and then gives…

This article discusses GeoGebra's geometry capabilities to assist the teaching issues and learning of geometry and measurement content in grades 5-9. Within this geometry context, the authors focus on using learning goals to select applets from a large public database. Also mentioned are some common pitfalls to avoid, such as error-prone applets.