This publication is the first part of a series "Mathematics - Pre-Kindergarten, Kindergarten, and Grade One." This bulletin is a part of the developing curriculum program that incorporates the pre-kindergarten into the educational system and reorganizes mathematics materials in the early childhood years. Part One of the program presented in this bulletin deals mainly with sets and subsets, numbers in sets, and number names. Part Two, published in 1967, deals with numbers and operations with numbers, early levels of number-line concepts, geometric concepts and fractional parts. It is expected that this material will serve as a sound foundation for future curriculum developments in the area of mathematics. (RP)