The Radio Mathematics Project was established to design, implement, and evaluate a prototype system of teaching elementary mathematics using radio as the major medium of instruction. The project, working in rural and urban primary schools in Nicaragua, presents daily mathematics lessons in second and third grade classrooms. Each lesson has a 30 minute broadcast portion followed by teacher-led activities specified in a teachers' guide. The project has directed its work towards simplifying the program and decreasing the cost of its use to make implementation possible by even the poorest nations. Evaluation results indicate children learning by radio score significantly higher on a test of mathematics achievement than those in traditional classrooms. Teachers of experimental classes support the use of radio lessons and recommend use of the program by other teachers. (Author)