Talk:Roman numerals/Archive 4

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Is MIM ok for 1999?

The article said:

Some rules regarding Roman numerals state that a symbol representing 10x may not precede any symbol larger than 10x+1. For example, one should represent the number "ninety-nine" as XCIX, not IC. However, these rules are not universally applied.

The last sentence is wrong. MIM for 1999 is not kosher, any way you look at it. So I removed the last sentence. Egil 07:31, 3 Feb 2005 (UTC)

That last sentence reflects that fact that - "kosher" or not - some people do it anyway. Since the role of Wikipedia is not to proclaim what's right, but to describe what's done, I've restored a slightly modified version of that statement. Tverbeek 15:20, 3 Feb 2005 (UTC)

I beg to disagree. There is no reason to report usage that is patent nonsense, unless in very particular cases. The statement However, these rules are not universally followed is just as bad as the previous one. As far as I know, the only usage of 'MIM' and 'IMM' is by people who haven't even bothered finding out what roman numbers really are. The 'pedia should report correct information. Your sentence gives the impression there is doubt about what the correct usage is. This is misleading. And if you feel the need to state that "People do not always bother following rules", it should be done in the context of human behaviour in general. -- Egil 17:23, 3 Feb 2005 (UTC)

One point of that section is that the question of "correct" usage isn't as simple as you state. Not only has usage varied somewhat with time and place, the Romans themselves exhibited some inconsistency in their usage, and a degree of personal preference seems to have been involved. Certainly we can and should spell out the usage that's most prevalent, but since no one can find the original RFC or ISO standard for them, the position that there is an indisputable standard for "correct" usage - and that you have it - seems hard to justify. Tverbeek 20:52, 3 Feb 2005 (UTC)

Tverbeek is right: Even today, there no indisputable standard defining these rules. Moreover, the only documents I know who codify these rigid rules are modern. Are there any Roman documents known who describe the Roman numbering systems? If so, do they codify the stringent rules, or do they allow IM etc., or don't they mention the problem? Are there any medieval documents known who describe the Roman numbering systems? Same questions apply. -- Adhemar, 12 December 2005

The usage XIIX for 18 is attested in actual usage in medieval times, and I think IC for 99 is also. People who actually wrote and read these numerals could communicate unambiguously with a slightly more flexible version of "The Rules", so who are we to be throwing around epithets such as "patent nonsense"? My guess is that "The Rules" were written by printers round about the time that they standardized spelling. Tverbeek is right. Cbdorsett 07:09, 6 Feb 2005 (UTC)

I came across a photo of an ancient inscription with the numeral XIIX (the tomb of Secundinus on the Via Appia). Does anyone know of an ancient example of the use of IC, IM or XM? --Zundark 14:03, 6 Feb 2005 (UTC)
In Rome, archway number 29 of the Colosseum has the inscription XXVIIII. The MathWorld article on Roman numerals cites (Menninger 1992, p. 281; Cajori 1993, p. 32) that "Romans occasionally wrote IM, IIM, etc." -- Adhemar, 12 December 2005

How about VL for 45? I for one don't think this is a 'decimal' system, so the rule about subtracting exactly one-tenth seems suspect. Aleš Wikiak 21:03, 25 August 2006 (UTC)

I was wondering the exact same thing. I've never seen VL or LD used before. Rather than trying to put it in terms of 10x and 10x+1, why not just explicitly spell out which letters may precede others. It's not like there are that many. I can precede V and X, X can precede L and C, and C can precede D and M. That's it. One short sentence. Alexwagner 13:16, 14 June 2007 (UTC)


In a printed book dated of 1668, I found the following: Nec aliter ediderat Fr. Raphelengius anno cIɔIɔxcyI What on earth did he mean with cIɔIɔxcyI? --Ciacchi 22:47, 10 August 2006 (UTC)

The first two 'signs' are obvious: cIɔ means 1000, and means 500. This means that xcyI somehow means 168. However, 168 should be CLXVIII according to the usual rules. It may be the result of a combination of typographic errors and some unknown rules. — Joe Kress 03:59, 11 August 2006 (UTC)
Assuming y is a badly written v (rather than some shorthand for 150), CIƆIƆXCVI would mean 1596. – Adhemar 18:20, 19 July 2007 (UTC)


How were roman numbers originally pronounced? For example, these days the number CMLX (1960) would just be pronounced as 'nineteenhundred sixty', because the reader first converts it to decimal notation, and pronounces the number accordingly. Did the romans actually say 'C M L X' ? 10:02, 6 November 2006 (UTC)

(not that anyone will read this) I would imagine that they used the Latin names for the numbers. Since most of the people were not literate, the speech in general probably wasn't affected much by the writing. But of course I'm conjecturing. Fishal 22:44, 17 May 2007 (UTC)
I think you're right, Fishal. If anyone pronounced CMLX cee em el ex, I imagine people would either think they were innumerate or joking. kwami 23:18, 17 May 2007 (UTC)

Chemistry use of IV

"As it relates to the nomenclature of inorganic compounds, only IV should be used. For example MnO2 should be named manganese (IV) oxide; manganese (IIII) oxide is unacceptable."

This explanation makes no sense at all, both IIII and IV represent 4. I have never seen IIII used to represent 4 in science literature, however without a source that states that only IV can be used I wouldn't say IIII is unacceptable. 09:56, 20 January 2007 (UTC)

Link to on line roman numeral calculator

There is a roman numeral calculator at:

I wanted to add this to external links but there is no edit link. Also, there is some vandalism on the page in the link section but I cannot get at the section to remove it so I hope that someone else can. —The preceding unsigned comment was added by JeanKorte (talkcontribs) 21:07, 4 February 2007 (UTC).

Movie Credits

"They are also sometimes used in the credits of movies and television programs to denote the year of production, particularly programs made by the BBC." It has been my own experience that they are not just sometimes, but very, very often used in such instances. I can't say anything for particularly the BBC, though. Is there any way this can be backed up? 23:35, 7 February 2007 (UTC)

I thought that roman numerals were often used in copyright notices (including movie credits) in order to obfuscate the actual year the movie was created so that people don't dismiss the movie as being outdated. Can anyone verify this? Jesushouston 00:56, 26 April 2007 (UTC)

Scheme code for conversion to Roman numerals

This code is in Scheme. I'm putting it here for verification before introducing into the main article. I claim this code with correctly romanize integers from 1 (I) to 3888 (MMMDCCCLXXXVIII), if not further. I submit that this code would improve the article by clearly and concisely exhibiting how romanization is performed. I wrote this code; any ownership I have is forfeit. Please respond with criticism/improvements and comments. When you feel the code has been sufficiently verified, please move it to the article. 02:51, 8 June 2007 (UTC)

(define romanize
  (lambda (n)
      [(>= n 1000) (string-append "M" (romanize (- n 1000)))]
      [(>= n 900) (string-append "CM" (romanize (- n 900)))]
      [(>= n 500) (string-append "D" (romanize (- n 500)))]
      [(>= n 400) (string-append "CD" (romanize (- n 400)))]
      [(>= n 100) (string-append "C" (romanize (- n 100)))]
      [(>= n 90) (string-append "XC" (romanize (- n 90)))]
      [(>= n 50) (string-append "L" (romanize (- n 50)))]
      [(>= n 40) (string-append "XL" (romanize (- n 40)))]
      [(>= n 10) (string-append "X" (romanize (- n 10)))]
      [(>= n 9) (string-append "IX" (romanize (- n 9)))]
      [(>= n 5) (string-append "V" (romanize (- n 5)))]
      [(>= n 4) (string-append "IV" (romanize (- n 4)))]
      [(>= n 1) (string-append "I" (romanize (- n 1)))]
      [else ""])))

Scheme code for conversion from Roman to Arabic numerals

This code is in Scheme. I'm putting it here for verification before introducing into the main article. I claim this code with correctly arabicize Roman numerals from I (1) to MMMDCCCLXXXVIII (3888), if not further. I submit that this code would improve the article by clearly and concisely exhibiting how arabicization is performed. I wrote this code; any ownership I have is forfeit. Please respond with criticism/improvements and comments. When you feel the code has been sufficiently verified, please move it to the article.

Please notice this is considerably more difficult than romanization! Notice that incorrectly formatted Roman numerals will fail, at the cost of some extra error-checking code. This could easily be removed if thought too confusing to be worthwhile. In particular, the error-checking has that I may only subtract V and X, X may only subtract L and C, and C may only subtract D and M. V, L, D, and M may not subtract. For example, given the incorrectly formatted numeral IC, this code will throw an error, not 99 (99 is properly written XCIX). Also note that only I, V, X, L, C, D, and M are supported.

Notice arabicizing the empty string will return 0. 21:38, 8 June 2007 (UTC)

(define arabicize
  (lambda (s)
    (let ([len (string-length s)])
        [(eq? 0 len) 0]
        [(eq? 1 len)
         (let ([fc (substring s 0 1)])
             [(string=? "I" fc) 1]
             [(string=? "V" fc) 5]
             [(string=? "X" fc) 10]
             [(string=? "L" fc) 50]
             [(string=? "C" fc) 100]
             [(string=? "D" fc) 500]
             [(string=? "M" fc) 1000]
             [else (error "Cannot parse incorrectly formatted Roman numeral")]))]
         (let ([fc (substring s 0 1)]
               [sc (substring s 1 2)]
               [restone (substring s 1 len)]
               [resttwo (substring s 2 len)])
             [(string=? "I" fc)
                [(string=? "V" sc) (+ 4 (arabicize resttwo))]
                [(string=? "X" sc) (+ 9 (arabicize resttwo))]
                  (string=? "L" sc)
                  (string=? "C" sc)
                  (string=? "D" sc)
                  (string=? "M" sc))
                 (error "Cannot parse incorrectly formatted Roman numeral")]
                [else (+ 1 (arabicize restone))])]
             [(string=? "V" fc) (+ 5 (arabicize restone))]
             [(string=? "X" fc)
                [(string=? "L" sc) (+ 40 (arabicize resttwo))]
                [(string=? "C" sc) (+ 90 (arabicize resttwo))]
                  (string=? "D" sc)
                  (string=? "M" sc))
                 (error "Cannot parse incorrectly formatted Roman numeral")]
                [else (+ 10 (arabicize restone))])]
             [(string=? "L" fc) (+ 50 (arabicize restone))]
             [(string=? "C" fc)
                [(string=? "D" sc) (+ 400 (arabicize resttwo))]
                [(string=? "M" sc) (+ 900 (arabicize resttwo))]
                [else (+ 100 (arabicize restone))])]
             [(string=? "D" fc) (+ 500 (arabicize restone))]
             [(string=? "M" fc) (+ 1000 (arabicize restone))]
             [else (error "Cannot parse incorrectly formatted Roman numeral")]))]))))

RoMaN nUmERals

Roman numerals is a numbers in a different language eg I is 1 II is 2 III is 3 IX is 4 and X is 5 ect.

Unicode chart

Should the chart be replaced with {{Unicode chart Number Forms}}:

Number Forms[1] chart (PDF)
  0 1 2 3 4 5 6 7 8 9 A B C D E F
1.^ As of Unicode version 6.3

I don't like how it looks, but that entire group of templates could use some cleanup. —Random832 14:27, 20 September 2007 (UTC)

other system?

i have read that R should mean 250 and N 900... [this unsigned entry was moved from the middle of an entry above]

You might be thinking of an alphabetical numbering system where A = 1, B = 2, etc., but in that case N would be 40, and R, 80. kwami 01:36, 3 October 2007 (UTC)