Roman numerals

Roman numerals on stern of a British clipper ship showing draft in feet. The numbers range from 13 to 22, from bottom to top.

The numeric system represented by Roman numerals originated in ancient Rome and remained the usual way of writing numbers throughout Europe well into the Late Middle Ages. Numbers in this system are represented by combinations of letters from the Latin alphabet. Roman numerals, as used today, are based on seven symbols: [1]

Symbol I V X L C D M
Value 1 5 10 50 100 500 1,000

The use of Roman numerals continued long after the decline of the Roman Empire. From the 14th century on, Roman numerals began to be replaced in most contexts by the more convenient Hindu-Arabic numerals; however, this process was gradual, and the use of Roman numerals persists in some minor applications to this day.

Roman numeric system

Basic decimal pattern

The original pattern for Roman numerals used the symbols I, V. and X (1, 5, and 10) as simple tally marks. Each marker for 1 (I) added a unit value up to 5 (V), and was then added to (V) to make the numbers from 6 to 9:

I, II, III, IIII, V, VI, VII, VIII, VIIII, X.

The numerals for 4 (IIII) and 9 (VIIII) proved problematic, and are generally replaced with IV (one less than 5) and IX (one less than 10). This feature of Roman numerals is called subtractive notation.

The numbers from 1 to 10 (including subtractive notation for 4 and 9) are expressed in Roman numerals as follows:

I, II, III, IV, V, VI, VII, VIII, IX, X. [2]

The system being basically decimal, tens and hundreds follow the same pattern:

Thus 10 to 100 (counting in tens, with X taking the place of I, L taking the place of V and C taking the place of X):

X, XX, XXX, XL, L, LX, LXX, LXXX, XC, C.

Note that 40 (XL) and 90 (XC) follow the same subtractive pattern as 4 and 9.

Similarly, 100 to 1000 (counting in hundreds):

C, CC, CCC, CD, D, DC, DCC, DCCC, CM, M.

Many numbers include hundreds, units and tens. The Roman numeral system being basically decimal, each "place" is added separately, in descending sequence from left to right, as with "arabic" numbers. For example the number 39 is XXXIX, (three tens and a ten less one), 246 is CCXLVI (two hundreds, a fifty less ten, a five and a one. There is, however no need for "place keeping" zeros, so "missing places" are simply omitted: thus 207, for instance, is written CCVII (two hundreds, a five and two ones) and 1066 becomes MLXVI (a thousand, a fifty and a ten, a five and a one) [3] [4]

Roman numerals for large numbers are nowadays seen mainly in the form of year numbers (other uses are detailed later in this article), as in these examples:

Alternative forms

A typical clock face with Roman numerals in Bad Salzdetfurth, Germany

The "standard" forms described above reflect typical modern usage rather than a universally accepted convention. Usage in ancient Rome varied greatly and remained inconsistent in medieval and modern times. [6]

  • Inscriptions dating from the Roman period not infrequently use "additive" forms such as IIII and VIIII for "4" and "9" instead of IV and IX. There are even instances of both forms appearing within the same document.
  • While in standard usage subtractive notation is limited to use of "adjacent" numerals, so that 99 (for example) is written XCIX, forms such as IC are not unknown.
  • XIIX or IIXX are sometimes used for "18" instead of XVIII. The Latin word for "eighteen" is often rendered as the equivalent of "twenty less two", which may be the source of this usage.
  • Sometimes V and L are not used, with instances such as IIIIII and XXXXXX rather than VI or LX. [7] [8]
An inscription on Admiralty Arch, London. The number is 1910, for which MCMX would be more usual.
  • Clock faces that use Roman numerals normally show IIII for four o’clock but IX for nine o’clock, a practice that goes back to very early clocks such as the Wells Cathedral clock of the late 14th century. [9] [10] [11] However, this is far from universal: for example, the clock on the Palace of Westminster in London (aka " Big Ben") uses a "normal" IV. [10]
  • At the beginning of the 20th century, different representations of 900 (conventionally CM) appeared in several inscribed dates. For instance, 1910 is shown on Admiralty Arch, London, as MDCCCCX rather than MCMX, while on the north entrance to the Saint Louis Art Museum, 1903 is inscribed as MDCDIII rather than MCMIII. [12]
Other Languages
Afrikaans: Romeinse syfers
Avañe'ẽ: Papaha Rómapegua
azərbaycanca: Rum rəqəmləri
Bân-lâm-gú: Lô-má sò͘-jī
беларуская (тарашкевіца)‎: Рымскія лічбы
български: Римски цифри
bosanski: Rimski brojevi
brezhoneg: Niveradur roman
dansk: Romertal
emiliàn e rumagnòl: Nùmer romàṅ
Esperanto: Romaj ciferoj
한국어: 로마 숫자
हिन्दी: रोमन अंक
hrvatski: Rimski brojevi
Bahasa Indonesia: Angka Romawi
interlingua: Numeration roman
қазақша: Рим сандары
Kiswahili: Namba za Kiroma
Lëtzebuergesch: Réimesch Zuelen
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Bahasa Melayu: Angka Rumi
Nederlands: Romeinse cijfers
日本語: ローマ数字
Nordfriisk: Röömsk taal
norsk: Romertall
norsk nynorsk: Romartal
Nouormand: Chiffes romaines
oʻzbekcha/ўзбекча: Rim raqamlari
Plattdüütsch: Röömsche Tallen
português: Numeração romana
română: Cifre romane
Gagana Samoa: Fuainumera o Roma
Sesotho sa Leboa: Lebadi la roma
sicilianu: Nùmmura rumani
Simple English: Roman numeral
slovenčina: Rímska číslica
slovenščina: Rimske številke
српски / srpski: Римски бројеви
srpskohrvatski / српскохрватски: Rimski brojevi
Türkçe: Roma rakamları
Tiếng Việt: Số La Mã
ייִדיש: רוימישע צאל
粵語: 羅馬數字
中文: 罗马数字