Definition of Roman Numerals

The Roman numeral system is internationally known and is based on seven letters that refer to the different numbers. In the present are not used frequently and are only used to to write dates and on some dials of classic watches. They can also be found in inscriptions on certain monuments, to indicate a new chapter in a book or in relation to official events (for example, reference to an edition of the Olympic Games).

The Roman numeral system

Each of the seven letters has a numerical value. Thus, the lyrics l equals 1, letter V equals 5, letter X equals 10, etc. Below is a table in which you can see all the equivalences.

Rules for writing Roman numerals

The rules for using this numbering are as follows:

1) According to the addition rule, a letter written to the right of another of equal or greater value, its value is added to this (for example, Xl is equal to 10 + 1 = 11 and CXV is equal to 100 + 10 + 5 = 115),

2) in the rule of subtraction, the letters l, X and C to the left of a higher value subtract its value (for example, lX is the same as 10 - 1 = 9, XC is the same as 100-10 = 90 and CD is equal to 500-100 = 400),

3) in the repetition rule the letters l, X, C and M can be written in a row a maximum of three times (for example, CCC is equal to 100 + 100 + 100 = 300), and

4) In the multiplication rule, a line above a letter or group of letters multiplies its value by 1000.

The origin of Roman numerals

Humans began to count as a necessity, especially in the activity commercial and numbers are used when they find that fingers or stones are of little use in calculating. The earliest written records of Roman numerals date back to the 11th century AD. C and it is believed that the Romans were not the real inventors but it is very possible that they were the Etruscans, a people that inhabited the north of present-day Italy and that ended up being subdued by the Romans.

Other numbering systems

The numbering systems are very diverse and from a historical point of view we can highlight the Egyptian numbering, the Indo-Arabic system, the numbering of the mayan or the current binary system.

In any case, the numbers are an abstraction of the mind that allow you to have control over reality.

Photos: iStock - Robert Zelichowski / susandaniels