Etruscan numerals

The first ten Etruscan numerals are the following

thu                            śa

zal                             senph

ci                               cezp

huth                          nurph

mach                         sar

An asimmetry is evident. Whereas the first five numbers have clearly no correspondant in indo-european languages, the last five are more familiar (sar for instance is similar to desa in sanscrit), and are probably loans. It seems, in other words, that the system of Etruscan had base five, and that only later it added the numbers from 6 to 10 with loans from the surrounding countries. This is confirmed by the fact that Latin numbers are obviously with base five: six is written VI (five and one), seven VII (five and two), etc. and Latin numbers are certainly of Etruscan origin.

A base five system can seem primitive, but it allows to count easily up to 25 on your fingers: it is enough to count the ones on one hand and the fives on the other. This is not possible with the decimal system, where you have to stop at 10 or to resort to an abacus or some other device. This mathematical ingenuity is consistent with the extraordinary engineering works of the Etruscans – many of the older realizations in Rome are in fact Etruscan, for instance the cloaca maxima.