Work began in 2005 on a research project that examines the effect of the Texas Instruments TI Navigator system on the teaching and learning of mathematics in an integrated high school curriculum. The TI-Navigator System provides wireless communication between students’ TI graphing calculators and the teacher’s PC, providing teachers with real-time feedback to instantly assess student understanding, and allowing students to contribute real-time to a shared workspace. Irene Mackay is using the system in the Laboratory School’s tenth grade classes, and studied the effects of the Navigator system on students’ understanding of matrix construction, operations, and interpretation; teachers’ assessment of student understanding; teachers’ instructional practices; students’ beliefs about mathematics; and student’s confidence in their mathematical ability. The project involved five weeks of observation and filming in the classroom, followed by ongoing analysis. Subsequent funding for continuing the work with TI Navigator and links with formative assessment is being sought. The proposal is based on preliminary findings from the current project.