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 puzzl...