High Quality Content by WIKIPEDIA articles! The Sand Reckoner is a work by Archimedes in which he set out to determine an upper bound for the number of grains of sand that fit into the universe. In order to do this, he had to estimate the size of the universe according to the then-current model, and invent a way to talk about extremely large numbers. The work, also known as Archimedis Syracusani Arenarius & Dimensio Circuli, is about 8 pages long in translation, is addressed to the Syracusan king Gelo II (son of Hiero II) and is probably the most accessible work of Archimedes; in some sense, it is the first research-expository paper.