One numbering system for the
Greeks was Milesian notation, using their
alphabet, plus three archaic letters, starting with alpha for the number one. This is pseudo decimal system, running from 1 to 9, then 10 to 90, then 100 to 900 and then repeating with a little single quote mark to show that your dealing with 1000s and beyond. The first archaic letter to be used is "6", the vau or digamma, the "F" above
is a digamma,
as is the weird snaky 'S'
Iota is the letter for "10".
A vau (or digamma) is a 'w' sound as in Wanax, the
ethnic of Elis, uses a vau.
There are also acrophontic numerals, but that is another story.