\begin{definition}[Definition:Greek Numerals/Classical Period]
The '''Greek numerals''' from the Classical period (c. $600$ BCE to c. $300$ BCE) are as follows:
:$\begin{array}{ccccccccc}
1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 & 9 \\
\alpha & \beta & \gamma & \delta & \epsilon & stigma & \zeta & \eta & \theta \\
\hline \\
10 & 20 & 30 & 40 & 50 & 60 & 70 & 80 & 90 \\
\iota & \kappa & \lambda & \mu & \nu & \xi & \omicron & \pi & koppa \\
\hline \\
100 & 200 & 300 & 400 & 500 & 600 & 700 & 800 & 900 \\
\rho & \sigma & \tau & \upsilon & \phi & \chi & \psi & \omega & sampi \\
\end{array}$
where $stigma$, $koppa$ and $sampi$ are characters that are not supported by MathJax.
These were the letters of the everyday Greek alphabet, with extra ones added from the Phoenician alphabet.
As it could be easy to confuse numbers with the letters of Greek words, a line was written over the numbers to distinguish them.
Numbers bigger than $999$ could be written by putting a stroke in front of the symbols.
\end{definition}