It's not at all like a Roman system except for the use of letters. You can separate a natural number n into two parts: n = 10 * q + k, where 0 <= k < 10 and q

It's not at all like a Roman system except for the use of letters. You can separate a natural number n into two parts: n = 10 * q + k, where 0 <= k < 10 and q in N q = 1 * K? + 2 * P? + 4 * T? + 8 * V? where K?, P?, T?, and V? are 0 if the letter is absent and 1 if the letter is present. n is a textbook base 10 decomposition, and q is a sparse binary representation. Roman numerals didn't use quotient/remainder or a geometric expansion at all. Since the 'base' seems to switch between 2 and 5 each time, you can't cleanly decompose it. And there was that weird subtractive case.