Masters, questions and challenges in the abacus schools

The mathematical scenario in Italy during the Late Middle Ages and the Renaissance is mainly dominated by the treatises on the abacus, which developed together with the abacus schools. In that context, between approximately the last thirty years of the XIVth Century and the first twenty years of the XVIth Century, the manuscript and printed tradition tells us of queries and challenges, barely known or totally unknown, in which the protagonists were abacus masters. We report in this work on the most significant examples, and draw out interesting cues for thoughts and remarks of a scientific, historical and biographical nature. Five treatises, written in the XVth and XVIth Century, have been the main source of inspiration for this article.