The ancient Greeks used the 24 letters of their alphabet plus three special signs called episemons--vau or digamma or stigma (6), koppa or qoppa (90), and san
or sampi (900)--as the basis of their numeral system (Cajori 1993, p. 23; Chrisomalis
2010, p. 134). Here, nine of the symbols represented the numbers 1-9, nine others
the numbers 10-90 by tens, and the remainder the numbers 100-900 by hundreds. The
addition episemons therefore allowed all values from 1 to 999 to be written by using
one to three of the 27 total characters.
For multiples of 1000, a small comma-like slanting sign known as a hasta was placed to the bottom left of a number symbol to indicate multiplication by 1000 (Chrisomalis
2010, p. 138).
In addition, the symbol M was use to represent one myriad, i.e.,
(Cajori 1993, p. 23).