How to Read Roman Numerals
Roman numerals were how the ancient Romans wrote down numerical values, and a modern version of this numerical system is still used today. Whether it’s on that building facade or a costume Roman period movie, here’s how to read Roman numerals quickly.
Learn the Values
Roman numerals use alphabet letters that are equivalent to a specific number. There are a limited number of alphabetical letters used, and each one are arranged in a way such that is equivalent to different numbers. That will be discussed later. For now, here are the roman numeral “letters” and their numerical equivalent.
I = 1
V = 5
X = 10
L = 50
C = 100
D = 500
M = 1,000
Pretty easy, right? Now let’s look at the rules that govern roman numerals.
How Roman Numerals Work
A Roman numeral is read from left to right, this will be an important rule to remember when dealing with big numbers in Roman numerals.
A Roman numeral can only be repeated thrice in succession to state a specific number. For example, to write the number 3 in Roman numerals, all you have to do is to repeat the equivalent of 1 three times. Hence, 3 = III, 20 = XX, 15 = VVV, 3,000 = MMM and so on and so forth.
Typically, Roman numerals are simply added together to form the number. For example, XV = 15 because X (10) and V (5) added together form 15. So if you want to form the number 23 in Roman numeral form, simple use two X’s (each equivalent to a ten) and 3 Roman numeral I’s. The result will be XXIII.
Roman numerals are typically arranged from the bigger number to the smaller number, and you read them accordingly.
However, when there is a Roman numeral placed before a Roman numeral of higher value, this simply means that you must subtract the equivalent of the smaller Roman numeral from the bigger Roman numeral from its right. For example, XL = 40, because L (50) is bigger than X (10). Really big numbers in Roman numerals can become a challenge because you need to learn how to distinguish these numbers, “cut” them up, and add them again, as illustrated in the next step.
Now, for the really tough stuff. We’ll work backwards with a number and put them in Roman numerals to let you see how it is written, to show you how it is read. For example, the number 749 will be written in Roman numerals as DCCXLIX. D is equal to 500, and since it follows a smaller Roman numeral C, it stands on its own. C and C is equivalent to 200. Now we see X and L, and we know that X ( equivalent to 10) is smaller than L (equivalent to 50), so it means that you must subtract 10 from 50, giving you 40, hence XL = 40. XL is followed by IX, and following the same rule, we subtract I (equivalent to 1) from X (equivalent to 10) so it means that IX = 9.
Broken down, DCCXLIX would read to = D (500) + C (100) + C (100) + XL (40) + IX (9) = 749.