Alcuin's Recreational Mathematics: River Crossings and Other Timeless Puzzles

Propositiones ad acuendos juvenes ("Problems to Sharpen the Young") is a ninth-century book written by medieval teacher and scholar Alcuin of York. Today, it has become one of the foundational texts in what is commonly called recreational mathematics. The book has been translated in many languages and analysed from various mathematical angles and perspectives, from contemporary arithmetic and geometry to the nature of sequences. It is not only a collection of ingenious and challenging puzzles, but the core ideas collected in this book have become major themes and branches of mathematics.

Here, Marcel Danesi revisits all fifty-three problems in Alcuin's original text, providing detailed solutions and analyses. Alcuin's Recreational Mathematics examines the problems in the Propositiones in easy-to-follow language, extracting from them the notions and techniques that today constitute basic mathematics. Each chapter discusses Alcuin's problems more broadly, and ends with ten exploratory puzzles based on Alcuin's original problems and related themes. Answers and detailed solutions are included at the back.

Alcuin's Recreational Mathematics demonstrates how Alcuin's Propositiones puts basic mathematical thinking on display via ingenious problems that often require outside-of-the-box thinking, constituting an original and imaginative investigation of mathematics in its essence.