This report presents a more detailed elaboration and discussion of the mathematical content of the central concepts which have been designated as the Mathematical Strands of the Mathematics Curriculum for grades K-8. In Part I of the report there is a discussion of the pedagogical philosophy which the committee felt was to have an importance equal to that of the mathematical content itself. In Part II the implications of that philosophy are readily apparent in the development of "strands," the basic cognitive subdivisions of the mathematics curriculum. Within each strand are listed examples to convey the general scope and sequential development of the mathematical content. The strands which have been selected are divided into two categories. The first category includes the strands of number and operation, geometry, measurement, and probability and statistics. The other category includes the strands of applications, sets, functions, logical thinking, and problem solving. (RP)