THE PURPOSE OF THIS PROJECT WAS (1) TO DEVELOP EDUCATIONAL MEDIA FOR TEACHING EDUCABLE MENTALLY HANDICAPPED (EMH) CHILDREN ARITHMETIC CONCEPTS AND (2) TO EVALUATE THE DEVELOPED PROGRAMED INSTRUCTIONAL MATERIALS. DURING THE FIRST PHASE OF THE STUDY THE ACTIVITIES WERE DEVOTED TOWARD ACCOMPLISHING THE FIRST PURPOSE, DEVELOPING THE EQUIPMENT AND MATERIALS. SEVERAL DEVICES AND COMBINATIONS OF DEVICES WERE USED DURING THE TRIAL PERIOD. THE DEVICE FINALLY DEVELOPED, REFERRED TO AS THE AUDIO-VISUAL MANIPULATIVE (AVM) DESK, PRESENTS INFORMATION ON A SCREEN THROUGH THE USE OF A SLIDE PROJECTOR. AUDIO MESSAGES ARE TRANSMITTED THROUGH EARPHONES AND A SPEAKER, AND THE CHILD MANIPULATES OBJECTS OR WRITES ON THE RESPONSE SURFACE. TWENTY-ONE DIFFERENT SEQUENTIAL ARITHMETIC PROGRAMS WERE DEVELOPED FOR THE DESK FOR TEACHING EMH CHILDREN SKILL SEQUENCES IN ARITHMETIC. DESK ADMINISTERED TESTS WERE ALSO DEVELOPED TO ASSESS THE CHILD'S UNDERSTANDING OF THESE CONCEPTS. OTHER MATERIALS DEVELOPED INCLUDE--(1) A MANUAL OF INSTRUCTIONS FOR TEACHERS (WHICH INCLUDES THE PROGRAM OBJECTIVES) AND (2) REINFORCEMENT MATERIALS FOR CLASSROOM USE. DURING THE EVALUATION PHASE OF THE STUDY, FOUR SEPARATE FIELD STUDIES WERE CONDUCTED. THE RESULTS OF THESE STUDIES SHOW--(1) THE AVM SYSTEM WAS AN EFFECTIVE VARIABLE IN PRODUCING DIFFERENTIAL RESULTS, (2) GOING THROUGH PROGRAMS TWICE DID PRODUCE HIGHER POST-TEST SCORES THAN GOING THROUGH THE PROGRAMS ONCE, (3) THE SYSTEM COULD BE USED EFFECTIVELY IN A CLASSROOM SETTING UNDER THE SUPERVISION OF CLASSROOM TEACHERS, AND (4) PROGRAMS DEVELOPED FOR EMH CHILDREN WERE NOT APPROPRIATE FOR TRAINABLE MENTALLY HANDICAPPED CHILDREN. THE APPENDIXES INCLUDE DETAILED INFORMATION ON THE DESK AND ARITHMETIC PROGRAMS. TWENTY-THREE REFERENCES ARE LISTED. (AUTHOR)