George Watson’s College is a mixed independent school and I have been using the TI-Nspire Navigator since October 2008 with most of my classes. In this lesson I used the Screen Capture feature.
The students own explorations led them to notice different features. Some  students thought that the rule was to do with multiples, or with odd and even numbers whilst others were able to come up with their own correct versions of the condition. By collecting back the students’ TI-Nspire files I gained an insight into their emerging thinking. The students were also beginning to become mathematically inquisitive and explore negative and decimal values for the lengths of the triangles’ sides.