2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/76236We discuss some examples that illustrate the countability of the positive rational numbers and related sets. Techniques include radix representations, Godel numbering, the fundamental theorem of arithmetic, continued fractions, Egyptian fractions, and the sequence of ratios of successive hyperbinary representation numbers.7 pagesHistory and Overview26A03 (Primary); 11A51, 11A55, 11A63 (Secondary)text