A project was designed to develop and validate a model for inservice education which could reach a large number of elementary school teachers. The thesis explored was whether this research, development, dissemination, and implementation could be effectively accomplished through the pooled competencies of a university-based staff, a state education agency, and local school systems. Analysis of data support the thesis. Procedures included the identification and description of four mathematical tasks to be included in the inservice program; construction of a behavioral hierarchy for one, the Algorithms Process Hierarchy (APH); construction of learning-teaching-instructional materials, "Games and Algorithms," for APH; initial tryout with 43 teachers in a summer institute; field testing in inservice programs in 11 countries with 211 teachers being taught by the summer institute participants. (Included are the complete findings, the pretest-posttest performance-based assessment instrument, hierarchies for the additional mathematical tasks [constructing and describing whirligigs, construction and description of 3-dimensional figures, and decisionmaking by probability], instructional materials for construction and description of whirligigs [which involves geometric shapes, linear measure, position on a grid, graph and slope of a line] procedures used for validating learning hierarchies, statistical formulas for the evaluation analysis, manipulative materials, and the "Games and Algorithms.") (JS)