The Attic (or Herodianic) system of numerals was the first system used in ancient Greece. "Attic" refers to the Greek territory of Attica, while "Herodianic" refers to Aelius Herodianus, a grammarian of the 2nd century A.D. who described the system in his writings.
This system, which arose around 600 B.C., used only six symbols. The number 1 was represented by a vertical bar, but the other five symbols were Greek letters. 5 was represented by (gamma), 10 by (delta), 100 by H (eta), 1000 by X (chi), and 10,000 (called a Myriad) by M (mu).
There were two ways of combining these six symbols into other
numbers. The first was that a small number at the top of gamma
represented a multiplier. For example,
represented 5 x 100, or 500. The second way was to write symbols
next to each other, like Roman numerals. For example,
There is no "standard" way of writing fractions with this numeral system, as this system was typically not used for representing fractions.
Attic numbers were replaced by the Ionic number system between 100 B.C. and 50 A.D.
More Greek mathematical history.