Products: TI-73. Target Level: Elementary Middle Grades. Authors: Melissa Nast (edited and revised). The activity workbook for the TI-73 with Graph Explorer Software highlight the capabilities of this calculator while integrating it into the mathematics curriculum in Grades 5 and 6. The activities in the book include topics in geometry and measurement number sense patterns and relations and probability and statistics. Each activity includes detailed keystrokes and separate student and teacher pages.