f57v - moon synodic period

[GregS]

Regarding considerations avove exressed, there certainly are systems in existence where numbers greater that nine are represented by single characters, e.g. the hexadecimal numbering system where we have A for 10 through F for 15. But this is something not from 15th century or older.

Well yes, hex obviously, but that is late 19th Century. I should have written something like 'in any number system which evolved naturally', as opposed to one invented by mathematicians. Particularly the rather odd base-18. The common bases are 5.10,12,20 and 60, and even the Mayans constructing symbols for 1-19 built them up logically, e.g. the symbol for 12 is the symbol for 2 over the symbol for 10.

Of course this proposed system is not really base-18 at all, or 531 would be 1-11-9. So it's just a simple substitution.

A dedicated symbol for zero, as to my knowledge, was not used back then in Europe, although in India it was used from the end of the first millennium AD.

Early 13th C. in Europe or threabouts, see Fibonacci and Sacrobosco. So that would be OK in the VMS.