"MATHEMATICS Pre-Calculus." . . "MATHEMATICS Reference." . . "MATHEMATICS Essays." . . . . . . . . . "Fundamental concepts of mathematics"@en . "Fundamental concepts of mathematics" . . . . "Electronic books"@en . . . "Basic concepts of number theory are discussed. Topics include set theory, mathematical induction, com-binatorics, arithmetic, real numbers, limit and convergence, and complex numbers."@en . . . . . . . . "Problems and exercises"@en . . "Matemàtica." . .