A concise work on important topics in number theory, this classic text was devised by a prominent mathematician to explain the essentials of mathematics in a manner accessible to high school and college students as well as to other readers. Clear-cut explanations cover natural numbers as cardinals, with discussions of positional notation and the ordering of numbers according to magnitude; natural numbers as ordinals, including Peano's axioms and the relation of ordinals to cardinals; the theory of numbers, encompassing prime numbers and their distribution, partitions of the circle, Fermat's simple and last theorems, perfect numbers, amicable numbers, and algebraic and ideal numbers; and rational numbers, with considerations of positive fractions, negative integers, and the field of rationals. 1955 ed.