1). The word (the Latin word meaning "none") was used to represent 0, although the earliest attested instances are medieval. For instance Dionysius Exiguus used alongside Roman numerals in a manuscript from 525 AD. About 725, Bede or one of his colleagues used the letter , the initial of or of (the Latin word for "nothing") for 0, in a table of epacts, all written in Roman numerals. The use of to indicate "none" long survived in the historic apothecaries' system of measurement: used well into the 20th century to designate quantities in pharmaceutical prescriptions. Fractions The base "Roman fraction" is , indicating . The use of (as in to indicate 7) is attested in some ancient inscriptions and also in the now rare apothecaries' system (usually in the form ): but while Roman numerals for whole numbers are essentially decimal does not correspond to , as one might expect, but . The Romans used a duodecimal rather than a decimal system for fractions, as the divisibility of twelve makes it easier to handle the common fractions of and than does a system based on ten . Notation for fractions other than is mainly found on surviving Roman coins, many of which had values that were duodecimal fractions of the unit . Fractions less than are indicated by a dot (·) for each "twelfth", the source of the English words inch and ounce; dots are repeated for fractions up to five twelfths. Six twelfths (one half), is for "half". Uncia dots were added to for fractions from seven to eleven twelfths, just as tallies were added to for whole numbers from six to nine. The arrangement of the dots was variable and not necessarily linear. Five dots arranged like (⁙) (as on the face of a die) are known as a quincunx, from the name of the Roman fraction/coin. The Latin words and are the source of the English words sextant and quadrant. Each fraction from to had a name in Roman times; these corresponded to the names of the related coins: Other Roman fractional notations included the following: Large numbers During the centuries that Roman numerals remained the standard way of writing numbers throughout Europe, there were various extensions to the system designed to indicate larger numbers, none of which were ever standardised. Apostrophus One of these was the apostrophus, in which 500 was written as , while 1,000