9731375 Schoen The PRIME-TEAM project is a two-year high school mathematics professional development and curricular implementation project for 65 lead teachers in nineteen Iowa schools/districts. As a Teacher Leadership project, it builds the teacher infrastructure needed for a future, planned scale-up and school-wide implementation of the Core-Plus instructional materials in participating schools/districts. Each participant is involved in 168 hours of comprehensive professional development through summer workshops, academic year activities, and reflective teaching of the Core Plus materials. Project evaluation utilizes protocols and instruments from the Local Systemic Change Core Evaluation, together with student achievement data from standardized, national instruments administered in each school/district. Cost sharing, derived primarily from participating districts/schools, is approximately 90% of the NSF request.