Claim: Attic numerals have different symbols for one, five, ten, fifty, 100, 500, etc; so to represent a number you keep adding the same symbol to itself until you get to the "fives" place, then you add the initial symbosl to the five symbols.
Evidence: The Attic numerals used the following main symbols, with the given values: 50 𐅄 500 𐅅