# Roman numerals

Long before the Arabs introduced their numbering system to Europe and this continent traveled to America and the rest of the world, thousands of years ago, in what was known as Ancient Rome , the Romans invented a numbering system the which we still use in many of the things. This numbering system is what we currently know by the name of Roman numerals .

## What are Roman numerals?

Roman numerals are a non-positional numbering system in which simple ideograms consisting of seven capital letters are used, each of which is represented by a numerical value .

• Definition
• Characteristics of Roman numerals
• Source
• History
• Who invented them
• What are they for
• Rules
• Operations with Roman numerals
• Importance
• Roman numerals from 1 to 50
• Roman numerals from 51 to 100
• Examples
• Curiosities

## Definition

Roman numerals are those that are considered as a non- positional numbering system in which the numbers are represented by means of simple ideograms consisting of seven capital letters , each of which corresponds to a numerical value .

## Characteristics of Roman numerals

The main characteristics of Roman numerals are the following:

• Roman numerals are made up of a series of letters that are: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1,000
• Each stripe that is placed on top of the number means that the figure is multiplied by a thousand.
• The order of placement of Roman numerals is always from highest to lowest value so that thousands are placed first, then hundreds, tens and units.
• In the writing of Roman numerals letters can never be repeated more than three times in a row.
• It is a non-positional system in which values ​​are assigned to certain letters.

## Source

Although we do not know exactly how the Roman numerals arose, we can say that they were most likely born from the Etruscan numeral system , although there are different versions that tell us about their adaptation by the Romans .

## History

Throughout the history of the Roman Empire , the number system, Roman numerals, was used, which was developed in ancient Rome and is still observed in some ancient buildings. This numbering system comes from Etruscan , since ancient writings of these peoples have been found that show that the Romans used the symbols of this culture to represent quantities , and later the Romans adapted them to their alphabet.

With the passage of time there are still references in which the use of this numerical system can be observed, although it is not a system that is used daily, but it can still be observed in some areas such as books , clocks and to mention centuries .

## Who invented them

Roman numerals were invented by the culture belonging to the Etruscans and then spread throughout Rome , Europe, and the rest of the world .

## What are they for

At present, Roman numerals have many different uses, among which we can mention the following:

• To name the centuries : they are used to name the number of the century in which we are or in which a certain matter happened. For example: we are in the 21st century, the French Revolution happened in the 18th century, Michelangelo painted the Sistine Chapel in the 16th century.
• To name the kings : Roman numerals are used to designate the generation of kings or very important characters in history, for example: Fernando II of Aragon, Felipe IV , Pope John Paul II .
• To number the volumes or parts of some books or films : they are also currently used to name chapters or volumes of this type of activity, for example: The Godfather II, Chapter IV of a thesis.
• For anniversaries, meetings or celebrations that are held periodically

## Rules

There are different rules regarding the function, use and also writing of Roman numerals, these rules are:

• Roman numeral symbols are written and must be read from left to right , from highest to lowest value.
• In Roman numerals when a lower value symbol is placed to the left of another, then it must be subtracted .
• The 5 symbols and their multiples (V, L, D) will always add up and cannot be placed to the left of a higher value one.
• When writing Roman numerals, only a maximum of three consecutive repetitions of the same symbol are allowed .
• A symbol in Roman numerals that appears by subtracting can only be repeated when its repetition is placed more than one symbol away to its right.
• Only a type 1 symbol (I, X, C, M) can be subtracted from the immediate major of type 1 or type 5 (V, L, D).
• The symbol I can only be used to subtract V and X.
• The symbol X can only be used to subtract L and C .
• The symbol C can only subtract D and M.

## Operations with Roman numerals

To perform operations using Roman numerals, it is important to know that by itself, the system could not reach the number 4,000, so when it is necessary to represent a high number, a horizontal line is added above the number to indicate that this number is multiplied. per thousand.

To be able to make a sum of Roman numerals, the following steps must be followed :

• Subtractions are converted into additions
• We link the two numbers that we want to add.
• We sort the symbols in descending order depending on their value.
• We do internal sums from right to left.
• We return to subtraction in the places where it is necessary to respect the writing rules described above.

To perform subtraction of Roman numerals we do the following:

• Convert the subtractions into additions .
• Symbols common to A and B must be eliminated
• For the largest symbol left in B we take the symbol of A greater than it and expand it. Then we apply step 2 again as many times as necessary.
• We go back to subtraction where necessary

To multiply Roman numerals is a bit more complicated and is usually multiplied and divided.

• It is divided between 2 and write the quotient of the division under A.
• Is multiplied B by 2 and write the result under B.
• Steps 1 and 2 are done again with the numbers that are obtained until a 1 appears in the left column.
• The resulting table is crossed out all the rows in which the number on the left is even.
• They will add the numbers that have left us in the right column.

To divide there are no general rules and the divisor must be subtracted from the dividend until we reach a number less than the divisor. The number of times we have subtracted will be the quotient of the division.

## Importance

The importance of Roman numerals is that they were the first numbering systems that were used in ancient times to add and keep accounts , in addition, they are currently a mechanism to number some important items such as book chapters, centuries and are also used in watches.

1. I
2. II
3. III
4. IV
5. V
6. SAW
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
44. XLIV
45. XLV
46. XLVI
47. XLVII
48. XLVIII
49. XLIX
50. L

1. L
2. LI
3. LII
4. LIII
5. LIV
6. LV
7. LVI
8. LVII
9. LVIII
10. LIX
11. LX
12. LXI
13. LXII
14. LXIII
15. LXIV
16. LXV
17. LXVI
18. LXVII
19. LXVIII
20. LXIX
21. LXX
22. LXXI
23. LXXII
24. LXXIII
25. LXXIV
26. LXXV
27. LXXVI
28. LXXVII
29. LXXVIII
30. LXXIX
31. LXXX
32. LXXXI
33. LXXXII
34. LXXXIII
35. LXXXIV
36. LXXXV
37. LXXXVI
38. LXXXVII
39. LXXXVIII
40. LXXXIX
41. XC
42. XCI
43. XCII
44. XCIII
45. XCIV
46. XCV
47. XCVI
48. XCVII
49. XCVIII
50. XCIX
51. C

## Examples

Some examples of Roman numerals are as follows:

• 8 is written VIII
• 36 is written XXXVI
• 752 is written DCCLII
• 2011 is written MMXI
• 49 is written IL
• 90 is written XC
• 99 is written IC
• 900 is written CM

## Curiosities

Some curiosities of Roman numerals are the following:

• They differ from the great numbering of history, because Roman symbols are written and read from left to right and are also always found from highest to lowest value.
• Roman numerals can be read from 1 and do not have or do not represent 0.