At 03:14 PM 5/30/2010, William Donzelli wrote: http://en.wikipedia.org/wiki/Roman_abacus Similar to the Japanese soroban, it says... and "undeniable proof that Romans were using a device that exhibited a decimal, place value system, and the inferred knowledge of a zero value as represented by a column with no beads in a counted position. Furthermore, the bi-quinary nature of the integer portion allowed for direct transcription from and to the written Roman numerals. No matter what the true usage was, what cannot be denied is that these instruments provide very strong arguments in favour of far greater facility with practical mathematics known and practised by the Romans." - John