TY - BOOK AU - Drooyan,Irving AU - Hadel,Walter TI - A programmed introduction to number systems SN - 0471222666 U1 - 512/.7/077 PY - 1973/// CY - New York PB - Wiley KW - Number theory KW - Programmed instruction N1 - includes bibliography and index ; 1. Preliminary concepts 2. The set of whole numbers 3. The set of integers 4. The set of rational numbers 5. The set of real numbers ER -