# Roman numerals

The Roman numerals is another way of writing the numbers that we know as such from 1 to 9. As in various cultures they had their own number system, the Roman is no exception, in fact to this day we continue to use it a lot in various things like to name centuries or to name kings.

## What are the roman numerals

All Roman numerals are made up of letters which each have a numerical value, these values are explained below:

It should be clarified that the Romans did not have zero in their system since it is not a positional system like the one we have for decimal since each position of our numbers tells us if they are units, tens, hundreds, etc. On the other hand, in the Roman system it is an additive system because to express 1001 they simply put MI without the need to indicate that between the two there is an absence of tens and hundreds.

## Roman numeral rules

• Roman numerals are written and read from left to right.

XXVI \ \rightarrow 20 + 5 + 1 = 26

• The numbers of value 1, 10, 100 and 1000 are the only ones that can be written 3 consecutive times. They may appear more times, but not consecutively. For example:

MMMCCCXXXIII \ \rightarrow \ 3333 \quad \checkmark

MMMCCCCXXXIII\ \rightarrow \ 3433 \quad \chi

MMMCDXXXIII \ \rightarrow \ 3433 \quad \checkmark

XXXIX \ \rightarrow \ 39 \quad \checkmark

• If there is a smaller number to the left of a larger number, the smaller number will be subtracted from the larger number.

IV \ \rightarrow \ 4 \quad \checkmark

IX \ \rightarrow \ 9 \quad \checkmark

XIX \ \rightarrow \ 19 \quad \checkmark

XIIX \ \rightarrow \ 18 \quad \chi

XVIII \ \rightarrow \ 18 \quad \checkmark

XXL \ \rightarrow \ 30 \quad \chi

XXX \ \rightarrow \ 30 \quad \checkmark

XLIX \ \rightarrow \ 49 \quad \checkmark

• The symbol I can only subtract from V and X.
• The symbol X can only subtract from L and C.
• The symbol C can only subtract from D and M.

## 4000 in roman numerals

To express quantities greater than 3999 (since it is the limit to write with all Roman numerals), the Romans placed a bar above the numbers to express numbers greater than 3999. For example, to express 4000 in Roman it is of the following way:

\overline{IV}

To express 4001 in Roman, simply place the bar on the IV and then write the I.

\overline{IV}I

## Roman numerals from 1 to 100

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