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Roman numerals are a Numeral System originating in ancient Rome , adapted from Etruscan Numerals . The system used in Classical Antiquity was slightly modified in the Middle Ages to produce the system we use today. It is based on certain letters which are given values as numerals. Roman numerals are commonly used today in numbered lists (in outline format), clockfaces, pages preceding the main body of a book, chord triads in music analysis, the numbering of movie publication dates, successive political leaders or children with identical names, and the numbering of some sport events, such as the Olympic Games or the Super Bowl . For arithmetics involving Roman numerals, see Roman Arithmetic and Roman Abacus . SYMBOLS There are seven basic Roman numerals. Multiple symbols may be combined to produce numbers in between these values, subject to certain rules on Repetition . In cases where it may be shorter, it is sometimes allowable to place a smaller, subtractive, symbol before a larger value, so that, for example, one may write ''IV'' or ''iv'' for ''four'', rather than ''iiii''. Again, for the numbers not assigned a specific symbol, the above given symbols are combined:
For large numbers (4000 and above), a bar is placed above a base numeral to indicate Multiplication by 1000:
For very large numbers, there is no standard format, although sometimes a double bar or underline is used to indicate multiplication by 1,000,000. That means an underlined X (X) is ten million. ORIGINS Although the Roman numerals are now written with letters of the Roman alphabet, they were originally separate symbols. The Etruscans , for example, used I Λ X 8 ⊕ for I V X L C M. They appear to derive from notches on ''. When the tallies were later transferred to writing, the marks were easily identified with the existing Roman letters I, V, X. (A Folk Etymology has it that the V represented a hand, and that the X was made by placing two Vs on top of each other, one inverted.) The tenth V or X along the stick received an extra stroke. Thus 50 was written variously as N, И, K, Ψ, , ''etc.'', but perhaps most often as a chicken-track shape like a superimposed V and I - . This had flattened to (an inverted T) by the time of Augustus , and soon thereafter became identified with the graphically similar letter L. Likewise, 100 was variously Ж, , , H, or as any of the symbols for 50 above plus an extra stroke. The form Ж (that is, a superimposed X and I) came to predominate, was written variously as >I< or , was then shortened to or C, with C finally winning out because, as a letter, it stood for (Latin for 'hundred'). The hundredth V or X was marked with a box or circle. Thus 500 was like a superposed on a or (that is, like a Þ with a cross bar), becoming a struck-through ZERO In general, the number Zero did not have its own Roman numeral, but a primitive form (nulla) was known by medieval Computists (responsible for calculating the date of Easter ). They included zero (via the Latin word meaning ''none'') as one of nineteen Epact s, or the age of the moon on March 22 . The first three epacts were nullae, xi, and xxii (written in Minuscule or lower case). The first known computist to use zero was Dionysius Exiguus in 525. Only one instance of a Roman numeral for zero is known. About 725, Bede or one of his colleagues used the letter N , the initial of ''nullae'', in a table of epacts, all written in Roman numerals. A notation for the ''value'' zero is quite distinct from the role of the ''digit'' zero in a Positional Notation system. The lack of a zero digit prevented Roman numerals from developing into a positional notation, and led to their gradual replacement by Hindu-Arabic Numerals in the early Second Millennium . On the other hand, the lack of positional notation may have prevented the Romans from developing a "zero". Which affected which is not certain. FRACTIONS Even though the Romans used a Decimal system for Whole Number s, reflecting Latin, they used a Duodecimal system for Fraction s, because the Divisibility of twelve (12 = 3×4) makes it easier to handle the common Fraction s of 1/3 and 1/4 than in a system based on ten (10 = 2×5). On Coin s, many of which had values that were duodecimal fractions of the unit , they used a notational system similar to that of whole numbers, but based on twelfths and one halves rather than units and fives. A dot • indicated an (one twelfth, the source of the English words ''inch'' and ''ounce''), and dots were added together up to five twelfths. Then one half (six twelfths) was notated using the letter S for ("half"). Dots were added to S for the fractions from seven to eleven twelfths, just as tallies were added to V for whole numbers from six to nine. Each of these fractions had its own name, which was also the name used for the corresponding coin: The names mean "ounce", "sixth", "quarter", "third", "five-ounce" (''quinquae unciae'' > ''quincunx''), "half", "seven-ounce" (''septem unciae'' > ''septunx''), "twice" (twice a third), "less a quarter" (''de-quadrans'' > ''dodrans'') or "ninth uncia" (''nona uncia'' > ''nonuncium''), "less a sixth" (''de-sextans'' > ''dextans'') or "ten uncias" (''decem unciae'' > ''decunx''), "less an ounce" (''de-uncia'' > ''deunx''), and "unit". The arrangement of the dots was variable and not necessarily linear. Five dots arranged like :·: (as on dice faces ) are known as a Quincunx from the name of the Roman fraction/coin. The Latin words ''sextans'' and ''quadrans'' are the source of the English words Sextant and Quadrant . Other Roman fractions include:
IIII OR IV? Roman numerals often appear in Crossword puzzles. For example, the answer to the clue "half of MCIV" would be "DLII", or the answer to the clue "Ovid's 552" would also be "DLII". MODERN NON-ENGLISH SPEAKING USAGE The above uses are customary for English-speaking countries. Although many of them are also maintained in other countries, those countries have additional uses for Roman numerals which are unknown in English-speaking regions. The Catalan , the French , the Portuguese , the Polish , the Romanian and the Spanish languages use capital Roman numerals to denote centuries. For example, 'XVIII' refers to the Eighteenth Century , so as to avoid confusion between the '18th century' and the '1800s'. (The Italians usually take the opposite approach, basing names of centuries on the digits of the years; for example is the common Italian name for , the Fifteenth Century .) Some scholars in English-speaking countries have adopted the former method, among them Lyon Sprague De Camp . In 1789 . This is how dates are inscribed on The Walls Of The Kremlin , for example. This method has the advantage that days and months are not confused in rapid note-taking, and that any range of days or months can be expressed without confusion. For instance, V-VIII is May to August, while 1-V-31-VIII is May first to August thirty-first. Note, though, that Spanish journalists use another format with the month's initial for certain dates even if it may be ambiguous: 11-M marks the bombing of trains in Madrid on '' 11 De Marzo de 2004'', not '' 11 De Mayo ''. In Eastern Europe , especially the Baltic nations, Roman numerals are used to represent the days of the week in hours-of-operation signs displayed in windows or on doors of businesses. Monday is represented by I, which is the initial day of the Week . Sunday is represented by VII, which is the final day of the week. The hours of operation signs are tables composed of two columns where the left column is the day of the week in Roman numerals and the right column is a range of hours of operation from starting time to closing time. The following example hours-of-operation table would be for a business whose hours of operation are 9:30AM to 5:30PM on Mondays, Wednesdays, and Thursdays; 9:30AM to 7:00PM on Tuesdays and Fridays; and 9:30AM to 1:00PM on Saturdays; and which is closed on Sundays. Since the French use capital Roman numerals to refer to the quarters of the year ('III' is the third quarter), and this has become the norm in some European standards organisation, the mixed Roman-Arabic method of recording the date has switched to lowercase Roman numerals in many circles, as '4-viii-1961'. ( ISO has since specified that dates should be given in all Arabic numerals, in ISO 8601 formats.) In Geometry , Roman numerals are often used to show lines of equal length. In Romania , Roman numerals are used for Floor Numbering . Likewise apartments in central Amsterdam are indicated as '138-III', with both an Arabic numeral (number of the block or house) and a Roman numeral (floor number). The apartment on the ground floor is indicated as ''. In Poland , Roman numerals are used for ordinals in names of some institutions. In particular high schools ("" - ''5th High School in Kraków''), tax offices ("" - ''2nd tax office in Gdańsk'') and courts ("" - ''District Court, 1st Civil Division'') - use Roman numerals. Institutions that use "" notation always use Arabic numerals. These include elementary ("") and middle schools (""). Roman numerals are rarely used in Asia . The Motion Picture Rating System in Hong Kong uses categories I, IIA, IIB, and III based on Roman numerals. ALTERNATE FORMS In the Middle Ages, Latin writers used a horizontal line above a particular numeral to represent one thousand times that numeral, and additional vertical lines on both sides of the numeral to denote one hundred times the number, as in these examples:
Sometimes was reduced to an Lemniscate symbol () for denoting 1,000. John Wallis is often credited for introducing this symbol to represent infinity (), and one conjecture is that he based it on this usage, since 1,000 was Hyperbolically used to represent very large numbers. Similarly, 5,000 () was reduced to ; and 10,000 () was reduced to In medieval times, before the letter ''j'' emerged as a distinct letter, a series of letters ''i'' in Roman numerals was commonly ended with a flourish; hence they actually looked like ''ij'', ''iij'', ''iiij'', etc. This proved useful in preventing fraud, as it was impossible, for example, to add another ''i'' to ''vij'' to get ''viij''. This practice is now merely an antiquarian's note; it is never used. (It did, however, lead to the Dutch Diphthong IJ .) TABLE OF ROMAN NUMERALS The "modern" Roman numerals, post- Victorian Era , are shown below: An accurate way to write large numbers in Roman numerals is to handle first the thousands, then hundreds, then tens, then units. Example: the number 1988. One thousand is M, nine hundred is CM, eighty is LXXX, eight is VIII. Put it together: MCMLXXXVIII. In Unicode Unicode has a number of characters specifically designated as Roman numerals, as part of the ''Number Forms'' range from U+2160 to U+2183 . For example, MCMLXXXVIII could alternatively be written as . This range includes both upper- and lowercase numerals, as well as pre-combined Glyphs for numbers up to 12 ( or XII), mainly intended for the clock faces for Compatibility with large East-Asian character sets such as JIS X 0213 that provide these characters. The pre-combined glyphs should only be used to represent the individual numbers where the use of individual glyphs is not wanted, and not to replace compounded numbers. Additionally, glyphs exist for alternate forms of 1000, 5000, and 10000. The characters in the range U+2160–217F are present only for Compatibility with other character set standards which provide these characters. For ordinary uses, the regular Latin letters are preferred. Displaying these characters requires a program that can handle Unicode and a Font that contains appropriate glyphs for them. GAMES After the Renaissance , the Roman system could also be used to write Chronogram s. It was common to put in the first page of a book some phrase, so that when adding the I, V, X, L, C, D, M present in the phrase, the reader would obtain a number, usually the year of publication. The phrase was often (but not always) in Latin, as chronograms can be rendered in any language that utilises the Roman alphabet. MNEMONIC DEVICES There are several Mnemonic s that can be useful in remembering the Roman numeral system. The following mnemonics recall the order of Roman numeral values above ten, with L being 50, '''C''' being 100, '''D''' being 500, and '''M''' being 1000.
A longer mnemonic helps to recall the order of Roman numerals from large to small.
REFERENCES SEE ALSO EXTERNAL LINKS
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