|Numeral systems by culture|
|East Asian numerals|
|List of numeral system topics|
|Positional systems by base|
|2, 4, 8, 16, 32, 64|
|1, 3, 9, 12, 20, 24, 30, 36, 60, more…|Symbol I V X L C D M Value 1 5 10 50 100 500 1,000
The Europeans still used Roman numerals even after the fall of the Roman Empire. From the 14th century, the Europeans replaced Roman numerals with Arabic numerals. However, people still use Roman numerals to this day.
I, II, III, IV, V, VI, VII, VIII, IX, X, XI, XII
Subtraction rule[change | change source]
Instead of writing the same letter four times, a rule for subtraction is used. The letter is written once, then the next largest Roman numeral is written. When a lower number (such as I) appears before a higher one (such as V), the lower number is subtracted from the higher one. For example, 4 is not written as IIII, but instead as IV, because IV is V (5) minus I (1). The same is done for 9 - it is not written as VIIII, but instead as IX, because IX is X (10) minus I (1).
Example[change | change source]
It is very easy to write a number as a Roman numeral. Simply subtract the largest possible Roman numeral as many times as possible from the number. This system will result in a valid Roman numeral, but will not take the subtraction rule into account.
|1 × 1000||+||1 × 500||+||4 × 100||+||1 × 50||+||3 × 10||+||4 × 1||=||1984|
Getting the number from the numeral is equally simple, by adding the values of the symbols.
In general, the values for 5, 50, and 500 are not subtracted. Here is the same number using the subtraction rule:
|1 × 1000||+||(1 × 1000) - (1 × 100)||+||1 × 50||+||3 × 10||+||(1 × 5) - (1 × 1)||=||1984|
Special values[change | change source]
Zero[change | change source]
Fractions[change | change source]
|Fraction||Numeral||Name (nominative and genitive)||Meaning|
|2/12 = 1/6||·· or :||Sextans, sextantis||"Sixth"|
|3/12 = 1/4||··· or ∴||Quadrans, quadrantis||"Quarter"|
|4/12 = 1/3||···· or ∷||Triens, trientis||"Third"|
|5/12||····· or ⁙||Quincunx, quincuncis||"Five-ounce" (quinque unciae → quincunx)|
|6/12 = 1/2||S||Semis, semissis||"Half"|
|7/12||S·||Septunx, septuncis||"Seven-ounce" (septem unciae → septunx)|
|8/12 = 2/3||S·· or S:||Bes, bessis||"Twice" (as in "twice a third")|
|9/12 = 3/4||S··· or S∴||Dodrans, dodrantis
or nonuncium, nonuncii
|"Less a quarter" (de-quadrans → dodrans)|
or "ninth ounce" (nona uncia → nonuncium)
|10/12 = 5/6||S···· or S∷||Dextans, dextantis
or decunx, decuncis
|"Less a sixth" (de-sextans → dextans)|
or "ten ounces" (decem unciae → decunx)
|11/12||S····· or S⁙||Deunx, deuncis||"Less an ounce" (de-uncia → deunx)|
|12/12 = 1||I||As, assis||"Unit"|
Large numbers[change | change source]
A number of numeral systems are developed for large numbers that cannot be shown with I, V, X, L, C, D and M.
Apostrophus[change | change source]
One of the systems is the apostrophus, in which D is written as IƆ (500) and M is written as CIƆ (1,000). In this system, an extra Ɔ means 500, and multiple extra Ɔs are used to mean 5,000, 50,000 etc.
Vinculum[change | change source]
Another system is the vinculum, in which V, X, L, C, D and M are multiplied by 1,000 by adding an overline.
Usage[change | change source]
- In the Baltics and Russia, the days of the week are often written as Roman numerals, with I being Monday.
- When writing dates by hand, the month is sometimes written as a Roman numeral, especially for dates written in day-month-year sequence. For example: 26.XI.2014 or XI.26.2014 = 26 November 2014.
- Some video games use Roman numerals to indicate the game position in a series. The most famous examples are Final Fantasy games (Final Fantasy VII, Final Fantasy VIII, Final Fantasy X, etc...).
- When movies or books are published, the year of publication or year of copyright may be written as a Roman numeral.
- When people write about Monarchs or Popes, Patriarchs, or other leading figures, they are sometimes counted with Roman numbers, e.g. Queen Elizabeth II (of England), Pope John Paul II, Pope Benedict XVI, Patriarch Alexius II (of the Russian-Orthodox church)
- In France, the centuries are sometimes written with Roman numerals (example : "XXe siècle" meaning "20th century", XVIIIe siècle = "18th century", etc...).
- In Poland, roman numerals are used to show the month in dates and as a short method of writing ordinals (i.e. VI instead of 6th).
- Unicode has a code block called Number Forms, which also contains representations of Roman numerals, at the positions U+2160 to U+2188.
Related pages[change | change source]
References[change | change source]
- Gordon, Arthur E. (1982). Illustrated Introduction to Latin Epigraphy. Berkeley: University of California Press. ISBN 0-520-05079-7.
Alphabetic symbols for larger numbers, such as Q for 500,000, have also been used to various degrees of standardization.
- "The Mathematical Tourist : IIII versus IV on Clocks". Ivars Peterson. 4 August 2010. Retrieved 31 May 2019.
Expressed as Roman numerals, the first twelve numbers are usually given as I, II, III, IV, V, VI, VII, VIII, IX, X, XI, XII. However, on many clock faces, when the numbers on the dial are in Roman numerals, IIII replaces IV.
- C. W. Jones, ed., Opera Didascalica, vol. 123C in Corpus Christianorum, Series Latina.
- "Merriam-Webster Unabridged Dictionary".
- Asimov, Isaac (1966). Asimov On Numbers (PDF). Pocket Books, a division of Simon & Schuster, Inc. p. 12.