This manual provides guidelines for implementing the instructional program in mathematics prescribed for the Basic Skills Project of the Phoenix, Arizona, Union High School District. The project supplements instructional efforts for students whose basic skills in reading, English/writing, and mathematics are in greatest need of improvement. The instructional program uses an individual diagnostic/prescriptive approach, and the manual describes the process of diagnosing student strengths and weaknesses through the preparation of diagnostic profiles and student folders. The following components of instruction and their implications for Title I classes are discussed: educational goals and objectives, instructional materials, activities, instructional diagnosis, learning time, evaluation, and time spent on a task. Also discussed are the maintenance of student records; the use of instructional aides; the conduct of Parent Advisory Council, staff, or inservice meetings; and monitoring procedures. Detailed Diagnostic Profile and Progress Record forms are presented for each unit in the mathematics course. The forms have been designed to provide data on progress toward goals identified for each student, information on students' current learning needs, and indicators of student behaviors in the course of instruction. (MJL)