The Roman civilization was one of the most prosperous in antiquity. They stood out for their advances in numerous areas: they invented newspapers, roads, aqueducts, Roman arches and also a numbering system that is still used today in certain contexts: the roman numerals.
But Do you know the rules of roman numerals? Next, we will review these rules and explain in detail the origin, evolution and correct way of using the roman symbols.
Origins of Roman symbols
The Roman numeral system comes from the Etruscans, an ancient people who inhabited the Italian peninsula before the expansion of Rome. The Etruscans used symbols such as I, Λ, X, Ψ, 8 and ⊕ to represent numbers, which were later adapted by the Romans.
Roman numerals stood out, among other things, for being a non-positional system, unlike the decimal system we use today. Instead of relying on the position of the numbers, the Romans added or subtracted symbols depending on their placement. In fact, the format we know evolved gradually, and it wasn't until the Middle Ages that numbers stabilized in the form we use today.
Roman numeral rules
The Roman numeral system may seem complicated at first, but once you understand the basic rules, it's quite simple. Below we explain the main rules of Roman numerals:
- Reading from left to right: Like our own numerical system, Roman numerals are read from left to right. This is not a problem in our culture, as our reading system follows the same direction.
- The symbols I, X, C and M can be repeated up to three times.For example, III represents the number 3, and XXX represents 30.
- The symbols V, L and D cannot be repeated. Therefore, you cannot write VV to represent 10, it is incorrect.
- Addition and subtraction according to position: If a smaller number is added to the right of a larger number, it is added. For example, VI (5 + 1) is 6. On the other hand, if the smaller number is on the left, it is subtracted. Example: IV (5 – 1) is equal to 4.
- To represent thousands or millions, a top line is used above the number, which means multiply by 1000. For example: V represents 5000.
Representation of large quantities
In addition to the basic rules, the Romans were also able to represent larger numbers. To do this, they used an upper bar over the symbols, which multiplied the value of the number by 1000.
| Roman numeral | Decimal | Nomination |
| V | 5000 | Five thousand |
| X | 10.000 | Ten thousand |
| L | 50.000 | Fifty thousand |
| C | 100.000 | Hundred thousand |
| D | 500.000 | Five hundred thousand |
| M | 1.000.000 | One million |
By using these bars, the Romans were able to represent much larger amounts, including millions. For example, X represented 10.000, and MM would be two million.
The duodecimal system for fractions
An interesting fact about the Roman system is that they also had a duodecimal system to represent fractions. This system allowed the number to be divided into 12 equal parts, which facilitated the calculation of common fractions used in daily life, such as ¼ or ½.
To represent smaller fractions, the Romans used the symbol I for units and the letter S for halves (semis). Roman currency also followed this duodecimal system, using a "dot" to represent one ounce or one-twelfth of a coin.
Roman numerals today
Today, Roman numerals continue to find their place in century numbers, book chapters, names of Popes and Kings, movies and sporting events such as the Olympic Games or the Super Bowl.
- Names of Popes and Kings: John Paul II, Henry VIII.
- Centuries: 21st century, 13th century.
- Chapter Numbers: Chapter X, Chapter III.
- Events: Super Bowl LIV, XXIX Olympic Games.
Characteristics and curiosities of the Roman numeral system
It is obvious that the Roman numeral system It was used by the people who lived in the ancient times of the Roman empire. As a main characteristic we find that in this numerical system some letters are used as symbols for numbers.
It is also important to mention that Roman numerals are a decimal numbering system. What do we mean? In other words, they have tens, hundreds, thousands, and so on.
A curious fact that we should not fail to mention is that there is no number zero to designate the non-existence of elements (this number was known since Babylonian times, but it was only introduced as a number in India in the 900s and became known worldwide thanks to the Arabs, although it is known that the Dionysius monks Exiguus and Saint Bede in the year 525 and 725 used the symbol N to represent 0, but this is not used today).
Inside Roman numerals there are no negative numbers either. It is important to know that they are currently used for number the different volumes or books of an encyclopedia (Volume I, Volume II), we also use them for names of the Kings, Popes and other ecclesiastical figures (Pope Benedict XVI), for the acts and scenes from a play it is also used (Act I, Scene 2).
The Roman numeral system is used today for the congress appointment, Olympics and other events (II Congress of Medicine), we also make use of it for the numbering of different films of the same saga (Rocky, Rocky II, Rocky III and others), and others.
Roman numerals have an important cultural value, as they connect us to the past and remind us of the roots of our current numbering system. Although it is not a practical system for large mathematical calculations, its presence is assured in various areas of modern life.
Mastering the rules of Roman numerals will not only help you better understand history and culture, but will also give you a useful tool for reading and better understanding various forms of numbering still in use today.