 Another system was the "vinculum", in which conventional Roman numerals were multiplied by 1,000 by adding a "bar" or "overline".Although mathematical historian David Eugene Smith disputes that this was part of ancient Roman usage, the notation was certainly in use in the Middle Ages.Although modern usage is largely hypothetical it is certainly easier for a modern user to decode than the Apostrophus,


Another inconsistent medieval usage was the addition of "vertical" lines (or brackets) before and after the numeral to multiply it by 10 (or 100)