Publication Date



Technical Report: UTEP-CS-21-28

Published in Proceedings of the 14th International Workshop on Constraint Programming and Decision Making CoProd'2021, Szeged, Hungary, September 12, 2021.


Historically, to describe numbers, some cultures used bases much larger than our usual base 10, namely, bases 20, 40, and 60. There are explanations for base 60, there is some explanation for base 20, but base 40 -- used in medieval Russia -- remains largely a mystery. In this paper, we provide a possible explanation for all these three bases, an explanation based on the natural need to manage large groups of people. We also speculate why different cultures used different bases.