Roman numerals- numerals used by the ancient Romans in their non-positional number system.

Natural numbers are written by repeating these digits. At the same time, if a large number is in front of a smaller one, then they are added (the principle of addition), if the smaller one is in front of the larger one, then the smaller one is subtracted from the larger one (the principle of subtraction). The last rule applies only to avoid the fourfold repetition of the same figure.

Roman numerals appeared around 500 BC with the Etruscans.

To stick in memory letters digits in descending order, there is a mnemonic rule:

M s D arim With face-to-face L imony, X vatite V sem I X.

Respectively M, D, C, L, X, V, I

To correctly write large numbers in Roman numerals, you must first write down the number of thousands, then hundreds, then tens, and finally ones.

There is a "shortcut" for writing large numbers, such as 1999. It is not recommended, but is sometimes used for simplicity. The difference is that to reduce a digit, any digit can be written to the left of it:

• 999. Thousand (M), subtract 1 (I), get 999 (IM) instead of CMXCIX. Consequence: 1999 - MIM instead of MCMXCIX
• 95. One hundred (C), subtract 5 (V), get 95 (VC) instead of XCV
• 1950: Thousand (M), subtract 50 (L), we get 950 (LM). Consequence: 1950 - MLM instead of MCML

It was only in the 19th century that the number “four” was written universally as “IV”, before that the record “IIII” was most often used. However, the entry "IV" can be found already in the documents of the "Forme of Cury" manuscript dating back to 1390. Most watch dials traditionally use "IIII" instead of "IV", mainly for aesthetic reasons: this spelling provides visual symmetry with the numbers "VIII" on the opposite side, and the reversed "IV" is more difficult to read than "IIII".

Application of Roman Numerals

In Russian, Roman numerals are used in the following cases:

• Century or millennium number: XIX century, II millennium BC. e.
• The serial number of the monarch: Charles V, Catherine II.
• Volume number in a multi-volume book (sometimes numbers of book parts, sections or chapters).
• In some editions - page numbers with the preface to the book, so as not to correct references inside the main text when changing the preface.
• Antique watch dial markings.
• Other important events or list items, such as: V postulate of Euclid, II World War, XXII Congress of the CPSU, etc.

In other languages, the scope of Roman numerals may differ, for example, in Western countries Roman numerals sometimes write the number of the year.

Roman Numerals and Unicode

The Unicode standard defines characters to represent Roman numerals as part of Numeric forms(English) Number Forms), in the area of ​​characters with codes from U+2160 to U+2188. For example, MCMLXXXVIII can be represented in the form ⅯⅭⅯⅬⅩⅩⅩⅧ . This range includes both lowercase and uppercase digits from 1 (Ⅰ or I) to 12 (Ⅻ or XII), including combined glyphs for compound numbers such as 8 (Ⅷ or VIII), mainly for compatibility with East Asian character sets in industry standards such as JIS X 0213 where these characters are defined. Combined glyphs are used to represent numbers that were previously made up of single characters (e.g. Ⅻ instead of its representation as Ⅹ and Ⅱ). In addition, glyphs exist for archaic 1000, 5000, 10000, big reversed C (Ɔ), late 6 (ↅ, similar to the Greek stigma: Ϛ), early 50 (ↆ, similar to to the down arrow ↓⫝⊥ ), 50,000, and 100,000. It should be noted that the small back c, ↄ is not included in Roman numeral characters, but is included in the Unicode standard as the uppercase Claudian letter Ↄ .

Characters in the range U+2160-217F are present only for compatibility with other standards that define those characters. In everyday life, ordinary letters of the Latin alphabet are used. The display of such characters requires software, which supports the Unicode standard, and a font containing glyphs corresponding to these characters.

Roman numerals often cause us difficulty.
But it is they that are usually used when numbering centuries and book chapters, when designating clothing sizes and steps in music.
Roman numerals are in our life. So it's too early to give them up. Easier to learn, understand and learn. What's more, it's easy.
So, to designate numbers in Latin, combinations of the following 7 characters are accepted: I (1), V (5), X (10), L (50), C (100), D (500), M (1000).
Why were Latin letters chosen to represent the numbers 5, 50, 100, 500 and 1000? It turns out that these are not Latin letters, but completely different signs. The fact is that the basis for the Latin alphabet (and it, by the way, exists in several versions - 23, 24 and 25 letters) was the Western Greek alphabet.

Thus, the three characters L, C, and M go back to the Western Greek alphabet. Here they denoted aspirated sounds, which were not in the Latin language. When the Latin alphabet was being formed, it was they who turned out to be superfluous. And they were adapted to denote numbers in the Latin script. Later, their spelling coincided with Latin letters. So, the sign C (100) became similar to the first letter of the Latin word centum (one hundred), and M - (1000) - to the first letter of the word mille (thousand). As for the sign D (500), it was half of the sign F (1000), and then it became similar to a Latin letter. The sign V (5) was only the upper half of the sign X (10).
In this regard, by the way, the popular theory that the name of the church office of the Pope (Vicarius Filii Dei), when replacing letters with Roman numerals, adds up to the “devil's number”, seems funny.

So, how to understand the Latin numbers?
If the sign denoting a smaller number is to the right of the sign denoting a larger number, then the smaller is added to the larger; if on the left, then subtract:
VI - 6, i.e. 5+1
IV - 4, i.e. 5-1
LX - 60, i.e. 50+10
XL - 40, i.e. 50-10
CX - 110 i.e. 100+10
XC - 90, i.e. 100-10
MDCCCXII - 1812, i.e. 1000+500+100+100+100+10+1+1.

There may be different meanings for the same number. So, the number 80 can be represented as LXXX (50+10+10+10) and as XXC(100-20).
Basic Roman numerals look like this:
I (1) - unus (unus)
II(2) - duo (duo)
III(3) - tres (tres)
IV (4) - quattuor (quattuor)
V (5) - quinque (quinque)
VI(6) - sex (sex)
VII (7) - septem (septem)
VIII (8) - octo (octo)
IX (9) - novem (novem)
X (10) - decem (decem), etc.

XX (20) - viginti (viginti)
XXI (21) - unus et viginti or viginti unus
XXII (22) - duo et viginti or viginti duo, etc.
XXVIII (28) - duodetriginta (duodetriginta)
XXIX (29) - undetriginta (undetriginta)
XXX (30) - triginta (triginta)
XL (40) - quadraginta (quadraginta)
L (50) - quinquaginta (quinquaginta)
LX (60) - sexaginta (sexaginta)
LXX (70) - septuaginta (septuaginta)
LXXX (80) - octoginta (octoginta)
XC (90) - nonaginta (nonaginta)
C (100) - centum (centum)
CC (200) - ducenti (ducenti)
CCC (300) - trecenti (trecenti)
CD (400) - quadrigenti (quadrigenti)
D (500) - quingenti (quingenti)
DC (600) - sexcenti (seccenti)
DCC (700) - septigenti (septigenti)
DCCC(800) - octingenti (octigenti)
CM (DCCCC) (900) - nongenti (nongenti)
M (1000) - mille (mille)
MM (2000) - duo milia (duo milia)
V (5000) - quinque milia (quinque milia)
X (10000) - decem milia (decem milia)
XX (20000) - viginti milia (viginti milia)
C (1000000) - centum milia (centum milia)
XI (1000000) - decies centena milia (decies centena milia)"

Elena Dolotova.

Roman numerals- numbers used by the ancient Romans in their non-positional number system.

Natural numbers are written by repeating these digits. At the same time, if a large number is in front of a smaller one, then they are added (the principle of addition), if the smaller one is in front of a larger one, then the smaller one is subtracted from the larger one (the principle of subtraction). The last rule applies only to avoid the fourfold repetition of the same figure.

Roman numerals appeared 500 BC from the Etruscans, who may have borrowed some of the numbers from the proto-Celts.

Roman numerals

no more than three times in a row no more than 3999 source not specified 2369 days

XXXII- in particular, this is how it is customary to highlight Roman numerals in Russian handwritten text (this is not used in typographical typesetting due to technical complexity). For other authors, the overline could indicate an increase in the value of the figure by 1000 times: V = 5000.

It was only in the 19th century that the number “four” was written universally as “IV”, before that the record “IIII” was most often used. However, the entry "IV" can be found already in the documents of the "Forme of Cury" manuscript dating back to 1390. Most watch dials traditionally use "IIII" instead of "IV", mainly for aesthetic reasons: this spelling provides visual symmetry with the numbers "VIII" on the opposite side, and the reversed "IV" is more difficult to read than "IIII". There is also a version that IV was not written on the dial because IV is the first letters of the name of the god Jupiter (IVPITER).

The smaller number can be written to the left of the larger one, then it should be subtracted from the larger one. In this case, only numbers denoting 1 or powers of 10 can be subtracted, and only the next two numbers in the number series to the subtracted (that is, the subtracted, multiplied by 5 or 10) can act as a minuend. Repetitions of a smaller number are not allowed. Thus, there is only six options using the "rule of subtraction":

• IV = 4
• IX = 9
• XL=40
• XC = 90
• CD=400
• CM=900

For example, the number 94 will be XCIV \u003d 100 - 10 + 5 - 1 \u003d 94 - the so-called "subtraction rule" (appeared in the era of late antiquity, and before that the Romans wrote the number 4 as IIII, and the number 40 as XXXX).

It should be noted that other methods of "subtraction" are not allowed; thus, the number 99 should be written as XCIX, but not as IC. However, today, in some cases, a simplified notation of Roman numbers is also used: for example, in the program Microsoft Excel when converting Arabic numerals to Roman numerals using the ROMAN() function, you can use several types of representation of numbers, from classical to highly simplified (for example, the number 499 can be written as CDXCIX, LDVLIV, XDIX, VDIV or ID). The simplification is that to reduce any digit, any other digit can be written to the left of it:

Cases of such notation of numbers (usually years) are often found in the credits of US television series. For example, for the year 1998: IIMM instead of MCMXCVIII.

Application

• Ordinal number of the monarch
• Corps number in the Armed Forces
• Blood group on the patches of the uniform of the military personnel of the Armed Forces of the Russian Federation
• Base of homeopathic dilutions (Conium X3, Aconium C200, etc.).
• In mathematical analysis, the number of the derivative above the third is sometimes written in Roman numerals.

Roman numerals were widely used in the USSR when indicating the date to indicate the month of the year, for example: 11 / III-85 or 9.XI.89, this can be seen on many archival documents of those times. In a similar way, through a slash, they also wrote down the date of the lesson in class journals, for example: 24/II. A special format was often used to indicate dates of life and death on tombstones, where the month of the year was also indicated by Roman numerals, for example: 18 6 X I I 78 ∼ 19 5 I I I 53 (\displaystyle 18(\frac (6)(XII))78\sim 19 (\frac (5)(III))53) . A similar format was used in medical certificates in the 1970s and 1980s.

With the transition to computer processing of information, date formats based on Roman numerals have practically fallen out of use.

In other languages, the scope of Roman numerals may differ. In Western countries, the number of the year is often written in Roman numerals, for example, on the gables of buildings and in the credits of film and video products.

In modern Lithuania, on road signs, on shop windows, on signboards of enterprises, days of the week can be indicated by Roman numerals.

Unicode

Numeric forms(English) Number Forms) in the area of ​​characters with codes from U+2160 to U+2188. For example, MCMLXXXVIII can be represented in the form ⅯⅭⅯⅬⅩⅩⅩⅧ. This range includes both lowercase and uppercase digits for the numbers 1 (Ⅰ or I) to 12 (Ⅻ or XII), including combined glyphs for compound numbers such as 8 (Ⅷ or VIII), mainly for ensuring compatibility with East Asian character sets in industry standards such as JIS X 0213, where these characters are defined. Combined glyphs are used to represent numbers that were previously made up of single characters (for example, Ⅻ instead of its representation as Ⅹ and Ⅱ). In addition, glyphs exist for archaic 1000, 5000, 10,000, big reverse C (Ɔ), late 6 (ↅ, similar to the Greek stigma: Ϛ), early 50 (ↆ, similar to down arrow ↓⫝⊥), 50,000, and 100,000. It should be noted that the small backward c, ↄ is not included in Roman numeral characters, but is included in the Unicode standard as the uppercase Claudian letter Ↄ.

Unicode Roman Numerals Code 0 1 2 3 4 5 6 7 8 9 A B C D E F Value 1 2 3 4 5 6 7 8 9 10 11 12 50 100 500 1000 U+2160 U+2170 Value 1000 5000 10000 100 6 50 50,000 100,000 U+2180

Displaying all of these characters requires software that supports the Unicode standard and a font that contains the corresponding glyphs (such as the Universalia font).

Regular Expressions

The regular expression for checking Roman numerals is ^(M(0,3))(D?C(0,3)|C)(L?X(0,3)|X)(V?I(0,3)| I)$ In Perl, you can use the regular expression m/\b((?:M(0,3)?(?:D?C(0,3)|C)?(?:L ?X(0,3)|X)?(?:I(0,3)?V?I(0,3)|I)))\b/gs.

transformation

To convert numbers written in Arabic numerals to Roman, special functions are used. For example, in the Russian version of Microsoft Excel, there is a function for this ROMAN ROMAN(argument).

JavaScript conversion functions var arab = ; var roman = ["I","IV","V","IX","X","XL","L","XC","C","CD","D","CM ","M"]; function arabToRoman(number) ( if(!number) return ""; var ret = ""; var i = arab.length - 1; while(number > 0) ( if(number >= arab[i]) ( ret + = roman[i]; number -= arab[i]; ) else ( i--; ) ) return ret; ) function romanToArab(str) ( str = str.toUpperCase(); var ret = 0; var i = arab .length - 1;var pos = 0;while(i >= 0 && pos< str.length) { if(str.substr(pos, roman[i].length) == roman[i]) { ret += arab[i]; pos += roman[i].length; } else { i--; } } return ret; } Аналогичные функции на Си (C89): #include const int arabar = { 1, 4, 5, 9, 10, 40, 50, 90, 100, 400, 500, 900, 1000}; const char *romanar = { "I", "IV", "V", "IX", "X", "XL", "L", "XC", "C", "CD", "D", "CM", "M"}; char *arab2roman(unsigned short int arab) { static char roman; const int m = sizeof(arabar)/sizeof(int)-1, arabmax=arabar[m]; const char romanmax=romanar[m]; int i, n; if(!arab) { *roman=0; return roman; } i=0; while(arab>arabmax) ( roman = romanmax; arab -= arabmax; ) n=m; while(arab > 0) ( if(arab >= arabar[n]) ( roman = romanar[n]; if(n&1) roman = romanar[n]; arab -= arabar[n]; ) else n--; ) roman[i]=0; return roman; ) unsigned short int roman2arab(char *roman) ( const int m = sizeof(arabar)/sizeof(int)-1; unsigned short int arab; int len, n, i, pir; len=strlen(roman); arab= 0; n=m; i=0; while(n >= 0 && i< len) { pir=n&1; if(roman[i] == romanar[n] && (!pir || roman == romanar[n])) { arab += arabar[n]; i += 1+pir; } else n--; } return arab; } Программа перевода арабских цифр в римские и наоборот type str2 = string; const Rims: array of str2 = ("M","CM","D","CD","C","XC","L","XL","X","IX","V","IV","I"," "); Arab: array of integer = (1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1, 0); var N, NI, I, J: integer; S: string; function Arab2Rim(N: integer) : string; var S: string; I: integer; begin S:= ""; I:=1; while N >0 do begin while Arab[I]"" do begin while Rims[I] = Copy(S, 1, Length(Rims[I])) do begin S:= Copy(S, 1+Length(Rims[I]) , 255); N:= N + Arab[I]end; I:=I+1end; Rim2Arab:= Nend; begin WriteLn("Translation from Arabic to Roman numerals. 1999 B_SA"); ( Write("Enter a number to convert:"); ReadLn(N);) for NI:= 26 to 46 do WriteLn(NI," = ",Arab2Rim(NI)," back ", Rim2Arab(Arab2Rim(NI)) ); end. Arabic to Roman conversion function in Pascal function Arab2Roman(arab:integer):string; var i:integer; d:integer; arab_str:string; arab_len:integer; begin Result:= ""; arab_str:= IntToStr(arab); arab_len:= Length(arab_str); for i:= 0 to arab_len-1 do begin d:= StrToInt(String(arab_str)); if (d+1) mod 5 = 0 then Result:= Copy("IXCM", 1+i, 1) + Copy("VXLCDM", i*2 + (d+1) div 5, 1) + Result else Result:= Copy("VLD", 1+i, d div 5) + Copy("IIIXXXCCCMMM", 1+i*3, (d mod 5)) + Result; end; end;

Arabic to Roman conversion function in BASIC (the most short code) 10 INPUT "ARABIC NUMBER: "; A$ 20 FOR I=0 TO LEN(A$)-1 30 X=VAL(MID$(A$,LEN(A$)-I,1)) 40 IF X=4 OR X=9 THEN B$= MID$("IXCM",I+1,1)+MID$("VXLCDM",I*2+(X+1)/5,1)+B$ 50 IF X4 AND X case 1999) to roman on XPath string-join(for $num in (1999) return (("","M","MM","MMM")[($num idiv 1000) mod 10+1], ( "","C","CC","CCC","CD","D","DC","DCC","DCCC","CM")[($num idiv 100) mod 10+1 ], ("","X","XX","XXX","XL","L","LX","LXX","LXXX","XC")[($num idiv 10) mod 10+1], ("","I","II","III","IV","V","VI","VII","VIII","IX")[$num mod 10 +1]), "") A function to convert an Arabic number (in this case 1999) to a Roman number in Perl use strict; use warnings; my $n = 1999; my $nums = [ ["", qw(I II III IV V VI VII VIII IX) ], ["", qw(X XX XXX XL L LX LXX LXXX XC) ], ["", qw(C CC CCC CD D DC DCC DCCC CM) ], ["", qw(M MM MMM) ] ]; my $i = 0; my @res = (); push @res, ($nums->[$i++][ ($n % 10, $n = int($n / 10)) ]) for 0 .. 3; print reverse @res; Class for converting an Arabic number (from 1 to 3999) into a Roman number in Java import java.util.*; public class IntegerConverter ( public static String intToRoman(int number) ( if (number >= 4000 || number iterator = units.descendingKeySet().iterator(); while (iterator.hasNext()) ( Integer key = iterator.next( ); while (number >= key) ( number -= key; result.append(units.get(key)); ) ) return result.toString(); ) private static final NavigableMap units; static ( NavigableMap initMap = new TreeMap<>(); initMap.put(1000, "M"); initMap.put(900, "CM"); initMap.put(500, "D"); initMap.put(400, "CD"); initMap.put(100, "C"); initMap.put(90, "XC"); initMap.put(50, "L"); initMap.put(40, "XL"); initMap.put(10, "X"); initMap.put(9, "IX"); initMap.put(5, "V"); initMap.put(4, "IV"); initMap.put(1, "I"); units = Collections.unmodifiableNavigableMap(initMap); ) ) Extension class for converting Roman numbers to Arabic and vice versa, on CSharp /// /// The class is intended for converting Arabic numbers to Roman numbers and vice versa /// /// /// The class initially contains the alphabet of Roman numbers that can determine Arabic numbers from 1 to 39999 /// If you need to expand the range, you can define additional notation for Roman numerals using /// the Basic Roman Numerals field public static class Roman Numerals ( /// /// Alphabet of basic Roman numerals /// The alphabet is built in the form dictionary The key of a dictionary is Arabic number(int), value - its corresponding /// Roman number (string) /// /// /// Contains the Roman notation for Arabic numbers 1*,4*,5*,9* - where "*" represents 0. ..N zeros /// When created, it contains the designation of numbers from 1 to 10000 (I...ↂ) from 1 to 39999. /// If you want to be able to work with large quantity Roman numerals, then you must add to the list /// additional symbols starting from 40000 without skipping the elements 1*,4*,5*,9*. /// public static SortedList BasicRomanNumbers ( get; set; ) static RomanNumber() ( BasicRomanNumbers = new SortedList(17); BasicRomanNumbers.Add(1, "I"); BasicRomanNumbers.Add(4, "IV"); BasicRomanNumbers. Add(5, "V"); Basic Roman Numbers.Add(9, "IX"); Basic Roman Numbers.Add(10, "X"); Basic Roman Numbers.Add(40, "XL"); Basic Roman Numbers.Add(50, "L "); BaseRomanNumbers.Add(90, "XC"); BaseRomanNumbers.Add(100, "C"); BaseRomanNumbers.Add(400, "CD"); BaseRomanNumbers.Add(500, "D"); BaseRomanNumbers.Add (900, "CM"); Basic Roman Numbers.Add(1000, "M"); Basic Roman Numbers.Add(4000, "Mↁ"); Basic Roman Numbers.Add(5000, "ↁ"); Basic Roman Numbers.Add(9000, "Mↂ" ); BasicRomanNumbers.Add(10000, "ↂ"); ) /// /// Calculates the maximum possible Roman number for the current Roman numeral alphabet. /// /// Maximum possible Roman number public static uint MaximumRomanNumber() ( int lastNumber = BasicRomanNumbers.Keys.Last(); int numberWithoutZeros = int.Parse(lastNumber.ToString().Replace("0","\0 ")); int tentative=0; switch(NumberNoZeros) ( case 1: tentative = lastNumber * 4 - 1; break; case 4: case 9: tentative = lastNumber; break; case 5: tentative = lastNumber + lastNumber / 5 * 3; break; default: break; ) return uint.Parse(pre.ToString().Replace("0", "9"));; ) /// /// Converts integer to Roman numeral /// / // Arabic number to be converted to Roman notation /// Generated when a number equal to "0" /// or a number greater than the maximum Roman number is passed as a parameter. /// A string representing a Roman number public static string ArabicRoman(this int numberArab) ( StringBuilder numberRoman = new StringBuilder(); //Exclude the "-" sign from the Arabic number and make it the first character of the Roman number if (numberArab< 0) { числоРимское.Append("-"); числоАраб = -числоАраб; } if (числоАраб == 0) throw new ArgumentOutOfRangeException("числоАраб", числоАраб, "Недопустимое значение аргумента: римские числа не могут быть равными\"0\""); else if (числоАраб >MaxRomanNumber()) throw new ArgumentOutOfRangeException("NumberArab", NumberArab, string.Format("Invalid argument value: Cannot set a Roman number greater than (0)", MaxRomanNumber())); //Decompose the Arabic number into its constituent Roman numbers and combine them into one string var requiredBasicRomanNumbers = from to in BasicRomanNumbers.Keys where k = 1) ( numberArab -= current; numberRoman.Append(BasicRomanNumbers[current]); ) ) return numberRoman .ToString(); ) /// /// Converts a Roman number to Arabic /// /// A Roman number to be converted to an int /// Generated when a non-Roman number is passed as a parameter /// An integer representing the Arabic notation roman number public static int roman to arabic(this string roman number) ( int arabic number = 0; sbyte negative = 1; string roman = roman number.Trim(); if (roman == "-") ( negative = -1; roman = roman. Substring(1); ) StringBuilder RomanNumber template = new StringBuilder(); foreach (int to in BaseRomanNumbers.Keys) ( int index = BaseRomanNumbers.Keys.IndexOf(to); string quantifier="?"; if (index == 0 | |(index % 4) == 0) quantifier="(0,3)";RomanNumber template.Insert(0, string.Format("(?((1))(2))?", to.ToString() , BaseRomanNumbers[k], quantifier)); ) //Ignore case + match must start at the beginning of the string patternRomanNumbers.Insert(0, "(?i)^"); //Match must be found at the end of the string patternP ImskogoNumber.Append("$"); // Simplified check. Does not check for errors such as IVII if (!Regex.IsMatch(Roman, RomanNumber template.ToString())) throw new FormatException(string.Format("Text \"(0)\" is not a Roman number",Roman number)); Match number = Regex.Match(Roman, RomanNumber template.ToString()); foreach (int to in BaseRomanNumbers.Keys) ( numberArab += number.Groups[to.ToString()].Length / BaseRomanNumbers[to].Length * to; ) return numberArab * negative; ) )

Roman numerals are:

Roman numerals- numbers used by the ancient Romans in their non-positional number system.

Natural numbers are written by repeating these digits. At the same time, if a large number is in front of a smaller one, then they are added (the principle of addition), if the smaller one is in front of the larger one, then the smaller one is subtracted from the larger one (the principle of subtraction). The last rule applies only to avoid the fourfold repetition of the same figure.

Roman numerals appeared 500 BC among the Etruscans.

Numbers

Roman numerals

In Russian, there are mnemonic rules for fixing the alphabetic designations of numbers in descending order:

M s D arim With face-to-face L imony, X vatite V sem I X.

M s D we eat C advice L ish X okay V well-mannered I individuals

Respectively M, D, C, L, X, V, I

Examples

To correctly write large numbers in Roman numerals, you must first write down the number of thousands, then hundreds, then tens, and finally ones.

In this case, some of the numbers (I, X, C, M) may be repeated, but no more than three times; thus, they can be used to write any integer no more than 3999(MMMCMXCIX). In the early periods, there were signs to indicate larger numbers - 5000, 10,000, 50,000 and 100,000 [ source unspecified 683 days] (then the maximum number according to the mentioned rule is 399,999). When writing numbers in the Roman numeral system, the smaller digit may be to the right of the larger one; in this case it is added to it. For example, the number 283 in Roman is written as CCLXXXIII, that is, 100+100+50+30+3=283. Here, the number representing a hundred is repeated twice, and the numbers representing ten and one, respectively, are repeated three times.

Example: number 1988. One thousand M, nine hundred CM, eight tens LXXX, eight units VIII. Let's write them together: MCMLXXXVIII.

Quite often, to highlight the numbers in the text, a line was drawn over them: LXIV. Sometimes the line was drawn both above and below: XXXII- in particular, this is how it is customary to highlight Roman numerals in Russian handwritten text (this is not used in typographical typesetting due to technical complexity). For other authors, the overline could indicate an increase in the value of the figure by 1000 times: VM = 6000.

It was only in the 19th century that the number “four” was written universally as “IV”, before that the record “IIII” was most often used. However, the entry "IV" can be found already in the documents of the "Forme of Cury" manuscript dating back to 1390. Most watch dials traditionally use "IIII" instead of "IV", mainly for aesthetic reasons: this spelling provides visual symmetry with the numbers "VIII" on the opposite side, and the reversed "IV" is more difficult to read than "IIII".

The smaller number can be written to the left of the larger one, then it should be subtracted from the larger one. In this case, repetitions of a smaller digit are not allowed. In Roman, the number 94 will be XCIV=100-10+5-1=94 - the so-called "subtraction rule" (appeared in the era of late antiquity, and before that the Romans wrote the number 4 as IIII, and the number 40 as XXXX). There are six ways to use the "subtraction rule":

• IV = 4
• IX = 9
• XL=40
• XC = 90
• CD=400
• CM=900

It should be noted that other methods of "subtraction" are not allowed; thus, the number 99 should be written as XCIX, but not as IC. However, nowadays, in some cases, a simplified notation of Roman numbers is also used: for example, in Microsoft Excel, when converting Arabic numerals to Roman using the “ROMAN ()” function, you can use several types of representation of numbers, from classical to highly simplified (for example, the number 499 can be written as CDXCIX, LDVLIV, XDIX, VDIV, or ID). The simplification is that to reduce any digit, any other digit can be written to the left of it:

• 999. Thousand (M), subtract 1 (I), get 999 (IM) instead of CMXCIX. Consequence: 1999 - MIM instead of MCMXCIX
• 95. One hundred (C), subtract 5 (V), get 95 (VC) instead of XCV
• 1950: One thousand (M), subtract 50 (L), we get 950 (LM). Consequence: 1950 - MLM instead of MCML

Roman numerals can also be used to write large numbers. To do this, a line is placed above those numbers that represent thousands, and a double line is placed above the numbers that represent millions. For example, the number 123123 would look like this:

And a million is like I, but not with one, but with two features at the head: I

Application

In Russian, Roman numerals are used in the following cases:

• Century or millennium number: XIX century, II millennium BC. e.
• The serial number of the monarch: Charles V, Catherine II.
• Volume number in a multi-volume book (sometimes numbers of book parts, sections or chapters).
• In some editions - page numbers with the preface to the book, so as not to correct references inside the main text when changing the preface.
• Antique watch dial markings.
• Other important events or list items, for example: V postulate of Euclid, World War II, XX Congress of the CPSU, Games of the XXII Olympiad, etc.
• Valency of chemical elements.
• The ordinal number of a step in the scale.

Roman numerals were widely used in the USSR when indicating the date to designate the month of the year: 11/III-85 or 9.XI.89. To indicate the dates of life and death on tombstones, a special format was often used, where the month of the year was also indicated by Roman numerals. With the transition to computer processing of information, date formats based on Roman numerals have practically fallen out of use.

In other languages, the scope of Roman numerals may have some peculiarities, for example, in Western countries, Roman numerals sometimes record the year number.

If we expand the numbers graphically, we get the following:

Unicode

The Unicode standard recommends using regular Latin letters to represent Roman numerals. However, the standard also includes special characters for Roman numerals as part of Numeric forms(English) Number Forms) in the area of ​​characters with codes from U+2160 to U+2188. For example, MCMLXXXVIII can be represented in the form ⅯⅭⅯⅬⅩⅩⅩⅧ. This range includes both lowercase and uppercase digits from 1 (Ⅰ or I) to 12 (Ⅻ or XII), including combined glyphs for compound numbers such as 8 (Ⅷ or VIII), mainly for compatibility with East Asian character sets in industry standards such as JIS X 0213, where these characters are defined. Combined glyphs are used to represent numbers that were previously made up of single characters (for example, Ⅻ instead of its representation as Ⅹ and Ⅱ). In addition, glyphs exist for archaic 1000, 5000, 10,000, big reverse C (Ɔ), late 6 (ↅ, similar to the Greek stigma: Ϛ), early 50 (ↆ, similar to to an arrow pointing down Template:Wmwwyairrufctr5ke4fuuUnicode), 50,000, and 100,000. Note that the small backward c, ↄ is not included in Roman numeral characters, but is included in the Unicode standard as the uppercase Claudian letter Ↄ.

Unicode Roman Numerals Code 0 1 2 3 4 5 6 7 8 9 A B C D E F Value 1 2 3 4 5 6 7 8 9 10 11 12 50 100 500 1000 U+2160 U+2170 Value 1000 5000 10000 - - 6 50 50 000 100 000 U+2160! U+2180

Displaying all of these characters requires software that supports the Unicode standard and a font that contains the corresponding glyphs.

Regular Expressions

The regular expression for checking Roman numerals is "^(?i)M(0,3)(D?C(0,3)|C)(L?X(0,3)|X)(V?I(0, 3)|I)$". In Perl, you can use the regular expression "m/((?i)M(0,3)(D?C(0,3)|C)(L?X(0,3)|X )(I|V?I(0.3)))/g".

transformation

To convert numbers written in Arabic numerals to Roman, special functions are used. For example, in the Russian version of Microsoft Excel, there is a function for this ROMAN(argument), in the English version of Microsoft Excel and in any version of OpenOffice.org Calc this function is called ROMAN(argument).

JavaScript conversion functions var arab = ; var roman = ["I","IV","V","IX","X","XL","L","XC","C","CD","D","CM ","M"]; function arabToRoman(number) ( if(!number) return ""; var ret = ""; var i = arab.length - 1; while(number > 0) ( if(number >= arab[i]) ( ret + = roman[i]; number -= arab[i]; ) else ( i--; ) ) return ret; ) function romanToArab(str) ( str = str.toUpperCase(); var ret = 0; var i = arab .length - 1;var pos = 0;while(i >= 0 && pos< str.length) { if(str.substr(pos, roman[i].length) == roman[i]) { ret += arab[i]; pos += roman[i].length; } else { i--; } } return ret; } Аналогичные функции на Си (C89): #include const int arabar = { 1, 4, 5, 9, 10, 40, 50, 90, 100, 400, 500, 900, 1000}; const char *romanar = { "I", "IV", "V", "IX", "X", "XL", "L", "XC", "C", "CD", "D", "CM", "M"}; char *arab2roman(unsigned short int arab) { static char roman; const int m = sizeof(arabar)/sizeof(int)-1, arabmax=arabar[m]; const char romanmax=romanar[m]; int i, n; if(!arab) { *roman=0; return roman; } i=0; while(arab>arabmax) ( roman = romanmax; arab -= arabmax; ) n=m; while(arab > 0) ( if(arab >= arabar[n]) ( roman = romanar[n]; if(n&1) roman = romanar[n]; arab -= arabar[n]; ) else n--; ) roman[i]=0; return roman; ) unsigned short int roman2arab(char *roman) ( const int m = sizeof(arabar)/sizeof(int)-1; unsigned short int arab; int len, n, i, pir; len=strlen(roman); arab= 0; n=m; i=0; while(n >= 0 && i< len) { pir=n&1; if(roman[i] == romanar[n] && (!pir || roman == romanar[n])) { arab += arabar[n]; i += 1+pir; } else n--; } return arab; } Программа перевода арабских цифр в римские и наоборот type str2 = string; const Rims: array of str2 = ("M","CM","D","CD","C","XC","L","XL","X","IX","V","IV","I"," "); Arab: array of integer = (1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1, 0); var N, NI, I, J: integer; S: string; function Arab2Rim(N: integer) : string; var S: string; I: integer; begin S:= ""; I:=1; while N >0 do begin while Arab[I]"" do begin while Rims[I] = Copy(S, 1, Length(Rims[I])) do begin S:= Copy(S, 1+Length(Rims[I]) , 255); N:= N + Arab[I]end; I:=I+1end; Rim2Arab:= Nend; begin WriteLn("Translation from Arabic to Roman numerals. 1999 B_SA"); ( Write("Enter a number to convert:"); ReadLn(N);) for NI:= 26 to 46 do WriteLn(NI," = ",Arab2Rim(NI)," back ", Rim2Arab(Arab2Rim(NI)) ); end. Arabic to Roman conversion function in Pascal function Arab2Roman(arab:integer):string; var i:integer; d:integer; arab_str:string; arab_len:integer; begin Result:= ""; arab_str:= IntToStr(arab); arab_len:= Length(arab_str); for i:= 0 to arab_len-1 do begin d:= StrToInt(String(arab_str)); if (d+1) mod 5 = 0 then Result:= Copy("IXCM", 1+i, 1) + Copy("VXLCDM", i*2 + (d+1) div 5, 1) + Result else Result:= Copy("VLD", 1+i, d div 5) + Copy("IIIXXXCCCMMM", 1+i*3, d mod 5) + Result; end; end;

A distinctive feature of this algorithm is that it does not use arrays (unless, of course, the string is considered an array of characters).

Function to convert Arabic to Roman in BASIC (the shortest code) 10 INPUT "ARABIC NUMBER: "; A$ 20 FOR I=0 TO LEN(A$)-1 30 X=VAL(MID$(A$,LEN(A$)-I,1)) 40 IF X=4 OR X=9 THEN B$= MID$("IXCM",I+1,1)+MID$("VXLCDM",I*2+(X+1)/5,1)+B$ 50 IF X4 AND X case 1999) to roman on XPath string-join(for $num in (1999) return (("","M","MM","MMM")[($num idiv 1000) mod 10+1], ( "","C","CC","CCC","CD","D","DC","DCC","DCCC","CM")[($num idiv 100) mod 10+1 ], ("","X","XX","XXX","XL","L","LX","LXX","LXXX","XC")[($num idiv 10) mod 10+1], ("","I","II","III","IV","V","VI","VII","VIII","IX")[$num mod 10 +1]), "") A function to convert an Arabic number (in this case 1999) to a Roman number in Perl use strict; use warnings; my $n = 1999; my $nums = [ ["", qw(I II III IV V VI VII VIII IX) ], ["", qw(X XX XXX XL L LX LXX LXXX XC) ], ["", qw(C CC CCC CD D DC DCC DCCC CM) ], ["", qw(M MM MMM) ] ]; my $i = 0; my @res = (); push @res, ($nums->[$i++][ ($n % 10, $n = int($n / 10)) ]) for 0 .. 3; print reverse @res; Class for converting Arabic number (from 1 to 3999) to Roman number in Java class ArabRome ( private int arabBase = (1000, 500, 100, 50, 10, 5, 1); private String romeBase = ("M", "D" , "C", "L", "X", "V", "I"); public String ArabToRome(int arab) ( int result = 0; int remainder = 0; String resultRome = ""; for(short i = 0; i0 && result=4 && result Extension class for converting Roman numbers to Arabic numbers and vice versa, on CSharp /// /// The class is intended for converting Arabic numbers to Roman numbers and vice versa /// /// /// The class is originally contains an alphabet of Roman numerals capable of defining Arabic numerals from 1 to 39999 /// If you want to expand the range, you can define additional notation for Roman numerals using /// the Basic Roman Numbers field public static class Roman Number ( /// /// Basic Roman Numbers Alphabet numbers /// The alphabet is built as a dictionary, the key of the dictionary is the Arabic number (int), the value is the corresponding /// Roman number (string) t Roman designation of Arabic numbers 1*,4*,5*,9* - where "*" represents 0...N zeros /// When created, it contains the designation of numbers from 1 to 10000 (I...ↂ) Since a single character cannot /// occur more than three times in a Roman number, you can initially convert numbers from 1 to 39999 into Roman format. /// If you want to be able to work with a large number of Roman numbers, then you must add to list /// additional designations starting from 40000 without skipping elements 1*,4*,5*,9*. /// public static SortedList BasicRomanNumbers ( get; set; ) static RomanNumber() ( BasicRomanNumbers = new SortedList(17); BasicRomanNumbers.Add(1, "I"); BasicRomanNumbers.Add(4, "IV"); BasicRomanNumbers. Add(5, "V"); Basic Roman Numbers.Add(9, "IX"); Basic Roman Numbers.Add(10, "X"); Basic Roman Numbers.Add(40, "XL"); Basic Roman Numbers.Add(50, "L "); BaseRomanNumbers.Add(90, "XC"); BaseRomanNumbers.Add(100, "C"); BaseRomanNumbers.Add(400, "CD"); BaseRomanNumbers.Add(500, "D"); BaseRomanNumbers.Add (900, "CM"); Basic Roman Numbers.Add(1000, "M"); Basic Roman Numbers.Add(4000, "Mↁ"); Basic Roman Numbers.Add(5000, "ↁ"); Basic Roman Numbers.Add(9000, "Mↂ" ); BasicRomanNumbers.Add(10000, "ↂ"); ) /// /// Calculates the maximum possible Roman number for the current Roman numeral alphabet. /// /// Maximum possible Roman number public static uint MaximumRomanNumber() ( int lastNumber = BasicRomanNumbers.Keys.Last(); int numberWithoutZeros = int.Parse(lastNumber.ToString().Replace("0","\0 ")); int tentative=0; switch(NumberNoZeros) ( case 1: tentative = lastNumber * 4 - 1; break; case 4: case 9: tentative = lastNumber; break; case 5: tentative = lastNumber + lastNumber / 5 * 3; break; default: break; ) return uint.Parse(pre.ToString().Replace("0", "9"));; ) /// /// Converts integer to Roman numeral /// / // Arabic number to be converted to Roman notation /// Generated when a number equal to "0" /// or a number greater than the maximum Roman number is passed as a parameter. /// A string representing a Roman number public static string ArabicRoman(this int numberArab) ( StringBuilder numberRoman = new StringBuilder(); //Exclude the "-" sign from the Arabic number and make it the first character of the Roman number if (numberArab< 0) { числоРимское.Append("-"); числоАраб = -числоАраб; } if (числоАраб == 0) throw new ArgumentOutOfRangeException("числоАраб", числоАраб, "Недопустимое значение аргумента: римские числа не могут быть равными\"0\""); else if (числоАраб >MaxRomanNumber()) throw new ArgumentOutOfRangeException("NumberArab", NumberArab, string.Format("Invalid argument value: Cannot set a Roman number greater than (0)", MaxRomanNumber())); //Decompose the Arabic number into its constituent Roman numbers and combine them into one string var requiredBasicRomanNumbers = from to in BasicRomanNumbers.Keys where k = 1) ( numberArab -= current; numberRoman.Append(BasicRomanNumbers[current]); ) ) return numberRoman .ToString(); ) /// /// Converts a Roman number to Arabic /// /// A Roman number to be converted to an int /// Generated when a non-Roman number is passed as a parameter /// An integer representing the Arabic notation roman number public static int roman to arabic(this string roman number) ( int arabic number = 0; sbyte negative = 1; string roman = roman number.Trim(); if (roman == "-") ( negative = -1; roman = roman. Substring(1); ) StringBuilder RomanNumber template = new StringBuilder(); foreach (int to in BaseRomanNumbers.Keys) ( int index = BaseRomanNumbers.Keys.IndexOf(to); string quantifier="?"; if (index == 0 | |(index % 4) == 0) quantifier="(0,3)";RomanNumber template.Insert(0, string.Format("(?((1))(2))?", to.ToString() , BaseRomanNumbers[k], quantifier)); ) //Ignore case + match must start at the beginning of the string patternRomanNumbers.Insert(0, "(?i)^"); //Match must occur at the end of the string patternP ImskogoNumber.Append("$"); // Simplified check. Does not check for errors such as IVII if (!Regex.IsMatch(Roman, RomanNumber template.ToString())) throw new FormatException(string.Format("Text \"(0)\" is not a Roman number",Roman number)); Match number = Regex.Match(Roman, RomanNumber template.ToString()); foreach (int to in BaseRomanNumbers.Keys) ( numberArab += number.Groups[to.ToString()].Length / BaseRomanNumbers[to].Length * to; ) return numberArab * negative; ) )

Notes

1. Unicode Standard, 15.3
2. 1 2 Unicode Number Forms
3. Perry, David J. Proposal to Add Additional Ancient Roman Characters to UCS.
4. For the first two lines
5. "Science and Life" N12 1986 p.95, V. Ptitsyn, Moscow
6. Author - Kuznetsov Evgeny A.
7. Author - Evgeny A. Kuznetsov, 1992

see also

• Symbols of ancient Roman monetary and weight units

• Numbers
• Number systems

What do the Roman letters L C D M mean?

These are numbers! - in the Roman numbering system, based on the use of Latin letters, has become one of the good reasons for replacing it with a more convenient decimal number system in this regard
In ascending order, these letters represent the following integers: I - one, V - five, X - ten, L - fifty, C - one hundred, D - five hundred, M - one thousand.
Roman numerals
The Roman numbering system using letters has been common in Europe for two thousand years. Only in the late Middle Ages, it was replaced by a more convenient decimal system of numbers for calculations, borrowed from the Arabs. But, until now, Roman numerals denote dates on monuments, time on clocks and (in the Anglo-American typographic tradition) pages of book prefaces. In addition, in Russian, it is customary to designate ordinal numbers with Roman numerals.
To designate numbers, 7 letters of the Latin alphabet were used: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1000. Intermediate numbers were formed by adding several letters to the right or left. First, thousands and hundreds were written, then tens and ones. Thus, the number 24 was depicted as XXIV. The horizontal line above the symbol meant multiplication by a thousand.
Natural numbers are written by repeating these digits. At the same time, if a large number is in front of a smaller one, then they are added (the principle of addition), if the smaller one is in front of the larger one, then the smaller one is subtracted from the larger one (the principle of subtraction). The last rule applies only to avoid the fourfold repetition of the same figure. For example, I, X, C are placed respectively before X, C, M to denote 9, 90, 900 or before V, L, D to denote 4, 40, 400. For example, VI \u003d 5 + 1 \u003d 6, IV \u003d 5 - 1 = 4 (instead of IIII). XIX = 10 + 10 - 1 = 19 (instead of XVIIII), XL = 50 - 10 = 40 (instead of XXXX), XXXIII = 10 + 10 + 10 + 1 + 1 + 1 = 33, etc.
Performing arithmetic operations on multi-digit numbers in this notation is very inconvenient. The system of Roman numerals is not currently used, with the exception, in some cases, of the designation of centuries (XV century, etc.), years AD. e. (MCMLXXVII etc.) and months when indicating dates (for example, 1.V.1975), ordinal numbers, and sometimes derivatives of small orders, greater than three: yIV, yV, etc.
How are Roman numerals written? -//elhow.ru/ucheba/matematika/kak-pishutsja-rimskie-cifry
.437000.ru/info/rim.php
__________________________
The Latin alphabet became isolated around the 7th century BC. e. and originally included only 21 letters: A, B, C, D, E, F, Z, H, I, K, L, M, N, O, P, Q, R, S, T, V and X.
://ladyretryka.ru/?p=10980

What number does the Roman numeral M stand for?

What number does the Roman numeral M stand for?

Alsu - sh

I already answered a similar question (see here). Briefly, I would like to answer this one.

I repeat a little.

Roman numerals, and there are only 7 of them, are easy to remember. Here are the letters of these numbers in descending order: M, D, C, L, X, V, I:

As we see, The Roman numeral, which is the capital letter M, represents the number 1000.

Now we give examples of numbers that are written in Roman numerals:

Now let's write:

This year's number 2015 , for example, would be written like this: ММХV

1941 - MSMXXXXXXI

1945 - MCMXXXXXXV

2987 - MMCMLXXXVII

2001 - MMI

Zolotynka

If the Roman numeral M stands alone, by itself, then its value will be 1000.

But: if M is preceded by a smaller number, as, for example, in this example, CM, then this will mean: 1000-100=900.

If C comes after M, then you need to add, therefore the value is 1000 + 100 = 1010.

C, as we remember, stands for a hundred.

Main rules: you can not put more than one smaller number in front of a larger number for subtraction. So, IIV does not mean 3.

In addition, tens, hundreds and thousands should be separated as separate elements (a smaller number cannot differ from a larger one by more than 10 times). This means that 99 is XCIX, 90 + 9, but can never be written as IC. Likewise, 999 cannot be an IM, and 1999 cannot be a MIM, and so on.

Natashau

We are used to using Arabic numerals. But the Roman ones still exist and are widely used, which are already almost two and a half thousand years old. Roman numerals are represented as letters. There are only seven such letters: I, V, X, L, C, D, M. Their specific location indicates the number. If these numbers are located separately from the rest, then they have the following values: I - 1, V - 5, X - 10, L - 50, C - 100, D - 500, M - 1000.

Beautiful glade

Roman numeral M (aka letter) means number 1000 .

In Roman calculus, very few letters are used to write numbers, there are only 7 of them. But to write large numbers in Roman letters, you need to add and subtract one number from another, which is not so easy without practice.

In Arabic, 10 characters are used to denote numbers and they can write any number without mathematical operations.

The Latin letter M in Roman numerals means "thousand", from the Latin mille..

And now this prefix is ​​​​widely used, for example, ppm - literally "from a thousand", and the word "million" also came from there, literally translated "a huge thousand", "thousand", and it's interesting how this word appeared, but that's another story ..

Athanasius44

Roman numerals are now rarely used anywhere; they have been supplanted by more convenient Arabic ones. Basically, they are used to name centuries, for example, the 5th century, the 12th century, and even in rare cases.

The letter M was the Roman word for a thousand. Two adjacent letters MM mean two thousand, MMM three thousand, and then even more difficult and fun.

Moreljuba

The Roman numeral M, of course, is familiar to us as a letter, but in the Roman numeral system it is still a number. So it means exactly one thousand. and it originates from a Roman numeral from such a Latin word as mille.

Ludmila 1986

The ancient Romans used the letters of the Latin alphabet to represent numbers. Roman numerals appeared around 500 BC.

In many languages, Roman numerals are used to record the number of the century (millennium), mark the dials, in mathematical analysis, important events.

buzzing bee

Roman L, C, D, M are not as common as the rest, M means the number 1000, MM means 2000, and MMM means 3000.

For example, the year 2017 will be denoted by Roman numerals MMXVII, 2018 will be Roman numerals MMXVIII.

Roman numerals, invented over 2500 years ago, were used by Europeans for two millennia, then were replaced by Arabic numerals. This happened because Roman numerals are quite difficult to write down, and any arithmetic operations in the Roman system are much more difficult to perform than in the Arabic numeral system. Despite the fact that today the Roman system is not often used, this does not mean at all that it has become irrelevant. In most cases, centuries are denoted by Roman numerals, but it is customary to write years or exact dates in Arabic numerals.

Roman numerals are also used when writing the serial numbers of monarchs, encyclopedic volumes, and the valency of various chemical elements. The dials of wristwatches also often use Roman numerals.

Roman numerals are certain signs with which they write decimal places and their halves. Only seven capital letters of the Latin alphabet are used for this. The number 1 corresponds to the Roman numeral I, 5 - V, 10 - X, 50 - L, 100 - C, 500 - D, 1000 - M. When denoting natural numbers, these numbers are repeated. So 2 can be written using two times I, that is, 2 - II, 3 - three letters I, that is, 3 - III. If the smaller number comes before the larger one, then the subtraction principle is used (the smaller number is subtracted from the larger one). So, the number 4 is depicted as IV (that is, 5-1).

In the case when a large number is ahead of a smaller one, they are added, for example, 6 is written in the Roman system as VI (that is, 5 + 1).

If you are used to writing numbers in Arabic numerals, then some difficulties may arise when you need to write centuries in Roman numerals, any number or date. It is very easy and very fast to convert any number from the Arabic system to the Roman system and vice versa using a convenient converter on our website.

On the computer keyboard, just go to English language to easily write any number in Roman numerals.

Apparently, the ancient Romans preferred straight lines, so all their numbers are straight and strict. However, Roman numerals are nothing more than a simplified representation of the fingers of a human hand. The numbers one through four resemble outstretched fingers, the number five can be compared with an open palm, where the thumb protrudes. And the number ten resembles two crossed arms. In European countries, when counting, it is customary to unbend your fingers, but in Russia, on the contrary, to bend.

We don't use Roman numerals often. And it seems that everyone knows that we traditionally denote centuries with Roman numerals, and years and exact dates with Arabic numerals. The other day I had to explain to Arabic :-)) and Chinese students what, for example, XCIV or CCLXXVIII :-)). I learned a lot of interesting things for myself when I was looking for material. I share :-)) Maybe someone else will need it :-))

Roman numerals

Roman numerals are special characters used to write decimal places and their halves. To designate numbers, 7 letters of the Latin alphabet are used:

Roman Numeral Number

I 1
V 5
X 10
L 50
C 100
D 500
M 1000

Natural numbers are written by repeating these 7 Roman numerals.

Mnemonic rule for memorizing the alphabetic symbols of Roman numerals in descending order (the author of the rule is A. Kasperovich):

M s
D we eat
C advice
L ish
X okay
V well-mannered
I individuals

Rules for writing numbers in Roman numerals:

If a larger number comes before a smaller one, then they add up (the principle of addition),
- if the smaller number comes before the larger one, then the smaller one is subtracted from the larger one (subtraction principle).

The second rule is applied in order to avoid repeating the same number four times. So, the Roman numerals I, X, C are placed respectively before X, C, M to denote 9, 90, 900 or before V, L, D to denote 4, 40, 400.

VI \u003d 5 + 1 \u003d 6,
IV = 5 - 1 = 4 (instead of IIII),
XIX \u003d 10 + 10 - 1 \u003d 19 (instead of XVIIII),
XL = 50 - 10 = 40 (instead of XXXX),
XXXIII = 10 + 10 + 10 + 1 + 1 + 1 = 33 etc.

It should be noted that even performing arithmetic operations on multi-digit numbers in this notation is very inconvenient. Probably, the complexity of calculations in the Roman numbering system, based on the use of Latin letters, became one of the good reasons for replacing it with a more convenient decimal number system in this regard.

The Roman numbering system, which dominated Europe for two thousand years, is now in very limited use. Roman numerals are used to designate centuries (XII century), months when indicating the date on monuments (21.V.1987), time on watch dials, ordinal numbers, derivatives of small orders.

Additional Information:

To correctly write large numbers in Roman numerals, you must first write down the number of thousands, then hundreds, then tens, and finally ones.

Example : number 1988. One thousand M, nine hundred CM, eighty LXXX, eight VIII. Let's write them together: MCMLXXXVIII.

Quite often, to highlight the numbers in the text, a line was drawn over them: LXIV. Sometimes the line was drawn both above and below: XXXII - in particular, this is how it is customary to highlight Roman numerals in Russian handwritten text (this is not used in typographic typesetting due to technical complexity). For other authors, the overline could indicate an increase in the value of the figure by 1000 times: VM = 6000.

Tissot watches with the traditional spelling "IIII"

Exist "abbreviated way" to write large numbers like 1999. It not recommended, but sometimes used for simplification. The difference is that to reduce a digit, any digit can be written to the left of it:

999. Thousand (M), subtract 1 (I), get 999 (IM) instead of CMXCIX. Consequence: 1999 - MIM instead of MCMXCIX
95. One hundred (C), subtract 5 (V), get 95 (VC) instead of XCV
1950: One thousand (M), subtract 50 (L), we get 950 (LM). Consequence: 1950 - MLM instead of MCML

This method is widely used by Western film companies when writing the year of release of the film in the credits.

It was only in the 19th century that the number “four” was written universally as “IV”, before that the record “IIII” was most often used. However, the entry "IV" can be found already in the documents of the "Forme of Cury" manuscript dating back to 1390. Most watch dials traditionally use "IIII" instead of "IV", mainly for aesthetic reasons: this spelling provides visual symmetry with the numbers "VIII" on the opposite side, and the reversed "IV" is more difficult to read than "IIII".

Another version.

To write whole numbers in Roman numeration, seven basic numbers are used:

I = 1
V=5
X=10
L=50
C=100
D=500
M=1000

However, some of the numbers (I, X, C, M) may repeat, but no more than three times, thus, they can be used to write any integer no greater than 3999 (MMMCMXCIX). When writing numbers in the Roman numeral system, the smaller digit may be to the right of the larger one; in this case it is added to it. For example, the number 283 in Roman is written like this:

i.e. 200+50+30+3=283. Here, the number representing a hundred is repeated twice, and the numbers representing ten and one, respectively, are repeated three times.

The smaller number can also be written to the left of the larger one, in which case it should be subtracted from the larger one. In this case, repetitions of a smaller digit are not allowed. Let's write the number 94 in Roman:

XCIV=100-10+5-1=94.

This so-called subtraction rule: it appeared in the era of late antiquity (before that, the Romans wrote the number 4 as IIII, and the number 40 as XXXX). There are six ways to use the "subtraction rule":

IV = 4
IX = 9
XL=40
XC = 90
CD=400
CM=900

It should be noted that other ways of "subtracting" are not allowed; thus, the number 99 should be written as XCIX, but not as IC. However, nowadays, in some cases, a simplified notation of Roman numbers is also used: for example, in Microsoft Excel, when converting Arabic numerals to Roman using the "ROMAN ()" function, you can use several types of representation of numbers, from classical to highly simplified (for example, the number 499 can be written as CDXCIX, LDVLIV, XDIX, VDIV, or ID).

From this it is clear that in order to avoid a 4-fold repetition, the maximum possible number here is 3999, i.e. MMMIM

Roman numerals can also be used to write large numbers. To do this, a line is placed above those numbers that represent thousands, and a double line is placed above the numbers that represent millions. For example, the number 123123 would look like this:
_____
CXXIIICXXIII

And a million is like Ī, but not with one, but with two features at the head.

Examples of writing numbers in Roman and Arabic numerals

Roman numerals Arabic numerals

I 1 unus
II 2 duo
III 3 tres
IV 4 quadrant
V 5 quinque
VI 6 sex
VII 7 septem
VIII 8 octo
IX 9 November
X 10 decem
XI 11 undecim
XII 12 duodecim
XIII 13 trade
XIV 14 quattuordecim
XV 15 quindecim
XVI 16 sedecim
XVII 17 septendecim
XVIII 18 duodeviginti
XIX 19 undeviginti
XX 20 viginti
XXI 21 unus et viginti
XXX 30 triginta
XL 40 quadraginta
L 50 quinquaginta
LX 60 sexaginta
LXX 70 septuaginta
LXXX 80 octoginta
XC90 nonaginta
C 100 centum
CC 200 ducenti
CCC 300 trecenti
CD 400 quadringenti
D 500 quingenti
DC 600 sescenti
DCC 700 septingenti
DCCC 800 Octingenti
CM 900 nongenti
M 1000 mille
MM 2000 duo milia
MMM 3000
MMMIM(largest number) 3999

Additional examples:

XXXI 31
XLVI 46
XXIX 99
DLXXXIII 583
DCCCLXXXVIII 888
MDCLXVIII 1668
MCMLXXXIX 1989
MMIX 2009
MMXI 2011