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Roman Numerals: Charts, History and Numerology

Do you need to write 2011 using Roman numerals? It's easy!

2011 = MMXI

Note the fact that if you use the Roman system the numer 2011 cannot be considered "lucky" as it is sometimes believed when two parts of a given number add up to the same value, which is clearly the case if you stick to the Arabic numerals:

2+0 = 1+1

It occurred to me that for the first time in his career as a novelist Dan Brown was in the position to be extremely capricious, even to the most ridiculous degree. Remember, Da Vinci Code was his first success, quite unexpectedly. Deception Point and Angels and Demons only became widely known after Dan Brown became famous for his third novel. Now, why not use this opportunity to pick an ISBN that would carry some symbolic meaning? Wouldn't that be a nice touch to what Dan Brown's publisher hopes to be a highly successful book?

One must keep in mind that ISBN numbers cannot be chosen randomly. Every publisher is assigned blocks of ISBNs, all of them usually contain similar sequences. So, Dan Brown would have to get quite creative. Still, it did not take long for me to discover one very striking fact. If you add up the digits in the ISBN of "The Lost Symbol" you get the number 34:


Anyone familiar with numerology will immediately notice that the universally accepted lucky number 7 can be based on 34:  3 + 4 = 7. Also, according to some, 34 "signifies realization of the man."  You can easily find more random minutiae connected with this number (e.g. in Dante's Commedia there are 34 cantos dedicated to Hell, while Purgatory and Paradise each get 33 cantos). But here is the most interesting fact. The numbers 1 through 16 can be arranged in the so called Jupiter's Table, a magic square where every line of numbers has the sum of 34:

16    3    2   13
  5  10   11    8
  9    6    7   12
  4  15   14    1

There are variations in the way the numbers are oriented in the square. Of course, "serious" numerologists use Hebrew letters with their numeric values.


Amulets containing the Jupiter table are supposed to bring wealth, prosperity etc. As far as I can tell, there are many Masonic amulets of this sort. One was supposedly owned by Joseph Smith, the founder of Mormonism.

A word of caution, however. When you write 34 using Roman numerals you get XXXIV, which in reverse reads VIX (XX), meaning "hardly", "with difficulty", "barely."  Even worse, 34/2 = 17 and 17(XVII) has been feared for quite some time because when you rearrange the letters you can get VIXI - "I have lived" (meaning "I am dead"), therefore the number 17 is often superstitiously avoided. What will happen with Dan Brown and his writing career? Time will tell, but let's hope that Dan Brown will not find himself singing Charley Patton's highly numerological "34 Blues":

"I ain't gonna tell nobody,
'34 have done for me
I ain't gonna tell nobody what
'34 have done for me
Took my roller, I was broke as I could be."


Because I  made this discovery when the book was not available yet I had no idea that Dan Brown uses this exact Jupiter Square as a clue in his book! All of a sudden, the number 34 encoded in the ISBN does not look so coincidental... Here is a fragment of Albrecht Dürer's Melencolia I described in the novel:

I will add something else here... Some folks are saying that the complete ISBN includes 978. It looks like this is simply a translation of the number into a different ISBN standard (ISBN-10 to ISBN-13). In fact, it is difficult to find a book that does not have 978 as the first digits of ISBN-13, thus rendering this part of the ISBN unchangeable.

See also: Knights Templar symbols.

One look at any mathematical formula in Roman numerals is enough to realize that to use this system for anything complex would be extremely difficult, if not impossible. It takes forever to simply right down most numbers! The truth is, the Romans were not overly patriotic when it came to number systems. All the feats of engineering, temples, arenas and palaces would have never become a reality were it not for the ample use of Greek numerals! Roman engineers and scientists were usually either Greeks or Greek-educated Romans (sometimes completely bilingual). The Greek system was much more versatile, compact and well suited for any calculations known to Ancient mathematicians.

Superbowl numbers - Roman numerals

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And for all of you sports fans out there, Superbowl numbers in Roman numerals, truly one of the major sources of interest towards the ancient numeric system. Of course, the very first Superbowl did not have a number at first, but the rest of the sure did. I believe every Superbowl also had an official logo.

1              =                 I

2              =                 II

3              =                 III

4              =                 IV

5              =                 V

6              =                 VI

7              =                 VII

8              =                 VIII

9              =                 IX

10           =                 X

11           =                 XI

12           =                 XII

13           =                 XIII

14           =                 XIV

15           =                 XV

16           =                 XVI

17           =                 XVII

18           =                 XVIII

19           =                 XIX

20           =                 XX

21           =                 XXI

22           =                 XXII

23           =                 XXIII

24           =                 XXIV

25           =                 XXV

26           =                 XXVI

27           =                 XXVII

28           =                 XXVIII

29           =                 XXIX

30           =                 XXX

31           =                 XXXI

32           =                 XXXII

33           =                 XXXIII

34           =                 XXXIV

35           =                 XXXV

36           =                 XXXVI

37           =                 XXXVII

38           =                 XXXVIII

39           =                 XXXIX

40           =                 XL

41           =                 XLI

42           =                 XLII

43           =                 XLIII

What made Roman numerals easy to use?

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When modern students are faced with having to learn the Roman system they often wonder how on earth anyone ever found this number notation convenient for any sort of calculations. The answer is actually rather simple. Yes, Roman numerals are not great for complicated calculations. However, they were extremely convenient when they were used at the time of their origin. Imagine having to carve Arabic numerals on wood or bark. Now imagine achieving the same objective using Roman numerals. The difference is striking. All the letters used in the Roman system can be carved with a few simple cuts: I, V, X, L, < (for C), |> (for D), M. There is evidence that a similar system was still used in the 19th century, in some rural communities in Italy, by shepherds who needed to keep track of their flocks. By the way, the simplicity of these symbols may indicate that they are not related to the Latin alphabet, but are rather independent of it, except perhaps C and M, which are probably dependent on the Latin words centum (one hundred) and mille (one thousand).

Roman numerals in sports: the infamous UF t-shirt

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Come Superbowl time, every football fan in the US is subject to a mandatory annual rediscovery of Roman numerals. Of course, the proper way of referring to Superbowl match-ups requires the use of this antiquated, yet beautiful system. Apparently, this yearly refresh course is not enough for some people. This t-shirt that was made by the University of Florida in 2006 should serve as a somber reminder of the sad state of affairs in our education when it comes to Roman numerals. Instead of MMVI (2006) these shirts were printed as shown, proudly displaying XXVI (26). To all math teachers out there, use this in class to prove to your students that not knowing how to use Roman numerals can can you fired!

Roman Numerals 1-25 ( I-XXV ) - a video

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Roman Numerals 1-25 are displayed in this video. Complete with the audio.

Roman numerals: a field guide

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The ultimate Roman numerals chart! This guide is an essential reference for everybody who has to deal with Roman numerals. Includes a Roman numerals chart (1-5000) and a look-up table of alphabetically arranged Roman numerals, with some variants and erroneous renditions.

Roman Numerals: a field guide

Roman Numeral 9 (and 4)

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It is usually assumed that the correct way of expressing number 9 in Roman numerals is IX. This assumption is generally correct, but very often you will see number 9 shown as VIIII. Although this looks quite strange and almost wrong to the modern eye, this was a completely valid way of writing 9 in Roman times. My theory is that using VIIII instead of IX creates a sense of a natural progression of numbers. If you decide to use this old convention for your own numbering purposes, make sure that instead of IV you use IIII for 4, otherwise the resulting numbers may look inconsistent.

Puzzles with Roman numerals

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This passage is taken from Number Stories of Long Ago, by David Eugene Smith:

Titus liked to puzzle a chum of his named Caius, and one day he asked him this question : " What is the number that becomes one more when one is taken away from it ?"

"Your head," replied Caius, "must be just plain wood."

But when Titus wrote IX on the stone pavement and said to Caius, "Now take away the I and tell me what you have left,"Caius saw that the wooden head had something in it after all.

Then Caius, remarking that he could think of many other numbers that would answer just as well, asked this question: "What is the number that becomes ten more when ten is taken away ? "Titus then asked Caius if he knew that half of nine was four, and Caius replied that he must be dreaming. But Titus pointed again to IX and asked Caius to take the upper half of it and see if it was not IV. Then Caius said that he could show that half of twelve was seven.

"That is nothing," said Titus; "half of thirteen is eight."

"That is easy," said Caius ; "but can you take one hundred from four hundred and
have five hundred left ?"

Roman Numeral Converter

Decimal ("What is the Roman numeral for...?"):

Roman ("What is this Roman numeral?"):


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