This explanation of finger counting is from Summa de arithmetica, proportioni et proportionalita, the major work of Luca Pacioli, Franciscan monk and teacher of mathematics (from 1477 to 1480 Professor of Mathematics at the University of Perugia). It was published in Venice in 1494.
Universidad Autónoma de Madrid (2003) Pacioli y el Renacimiento . http://www.uam.es/personal_pdi/ciencias/barcelo/pacioli/pacioli.html (accessed 22 September 2004)
Illustration: public domain