This booklet, one of a series, has been developed for the project, A Program for Mathematically Underdeveloped Pupils. A project team, including inservice teachers, is being used to write and develop the materials for this program. The materials developed in this booklet include (1) elementary properties of the exponent, (2) properties of the right triangle, (3) squares and square roots, (4) the Pythagorean Theorem, (5) the acute and the obtuse triangle, (6) length of a diagonal of a rectangular solid, and (7) activities involving the determination of areas formed by the squares of sides of triangles. Accompanying these booklets will be a "Teaching Strategy Booklet" which will include a description of teacher techniques, methods, suggested sequences, academic games, and suggested visual materials. (RP)