Roman numerals....
1 = I
2 = II
3 = III
4 = IV (or IIII on old clocks, watches and sundials)
5 = V
6 = VI
7 = VII
8 = VIII
9 = IX
10 = X
20 = XX
30 = XXX
40 = XL
50 = L
60 = LX
70 =...
The Etruscans did and they once ruled the Romans but the Romans continued to use the Etruscan system of numeracy after they rebelled and gained their freedom from the Etruscans.