From school we began to become familiar with the Roman numerals, which are characterized by being** represented with letters**. These numbers are used in various areas and for different purposes, such as in history to number centuries (eg “21st century”).

It is necessary to learn how to convert these Roman numerals to **Arabic numbers** to, in such a way, know what figures each one indicates within the decimal system. That is what we will do in this article, taking as a reference the **number XXIII**so don’t miss it!

## What number is XXIII?

Roman numerals are a number system used by the Romans in ancient times. To this day they are still valid, being composed of letters where **each value ascends in multiples of five** in the following order:

**I, V, X, L, C, D and M**where the values in Arabic numerals would correspond to**1, 5, 10, 50, 100, 500 and 1000**.

In this way we introduce a little the definition of** arabic numerals**, which correspond to the number system we usually use. Arabic numerals, or in **Arab**are those that we use in our day to day to, for example, mark the time, mark dates on the calendar, perform a fraction in mathematics, etc.

These so-called “numbers in Spanish” are composed of symbols that we know as “**natural numbers**“, which are made up of:

**0, 1, 2, 3, 4, 5, 6, 7, 8 and 9.**

Arabic numerals define their value depending on which or how many numbers make up the figure. In the same way, the Roman numerals also apply this type of system, although in a different way. He** roman number system** **has its rules **when writing values and, therefore, by following them you can easily convert a number from the decimal system to a Roman number and vice versa.

Now, the norms of the Roman numeral system indicate that if a smaller number is on the right side of a larger one, it must be **Add**. Otherwise, it **subtraction**.

- In the case of
**number XXIII**we have to “**x**” has a value of 10. If we join it with another “**x**“, both are added together and we would get the number 20. Now, to its right is the number ‘**II**‘ whose value is 3, since it is made up of three letters ‘**Yo**‘ which equal 1 each.

If we join both parts knowing that 3 is less than 10 and that being to its right must be added, we obtain that **the number XXIII has a value of 23**.

## What century is XXIII referring to?

When talking about **23rd century** This can be interpreted in two ways:

- As the century ‘a. C.’ (BC).
- As the century the ‘d. C.’ (after Christ).

On the one hand, the XXIII century AD. C. refers to a century that has not yet happened, since we are currently in the XXI. This **It will begin on January 1, 2201 AD. c.** and will culminate on December 31, 2300 AD. c.

On the other hand, the XXIII century B.C. c. **elapsed from January 1, 2300 a. c.** and culminated on December 31, 2201 a. C. From this time it is possible to highlight some events that were recorded in history, such as the beginning of the** use of metals in Northern Europe** or the fact that the Italian territory began to be inhabited by different peoples who laid the **foundations of Italian culture and civilization**.