When and How to Write Roman Numerals

I, V, X, L, C, D, and M

Understanding Roman Numerals
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Roman numerals have been around for a long time. In fact, as the name suggests, Roman numerals started in ancient Rome, between 900 and 800 B.C. They originated as a set of seven basic symbols for numbers.

As time and language progressed, those markings transformed into the letters we use today. While it may seem strange to use Roman numerals when numbers can be used, knowing how to use them can come in handy.

Roman Numerals in Everyday Life

Roman numerals are all around us and you've almost certainly seen and used them, even without realizing it. Once you familiarize yourself with the letters and their usage, you'll be surprised at how often they come up.

Below are several places that Roman numerals are often found:

  1. Roman numerals are often used in books, often to number the chapters.
  2. Pages in appendices or introductions are also numbered with Roman numerals.
  3. In plays, they separate acts into sections.
  4. Roman numerals can be seen on fancy clocks and watches. 
  5. Annual sporting events, like the Summer and Winter Olympics and the Super Bowl, also mark the passage of years by using Roman numerals. 
  6. Many generations have a family name that has been passed down and includes a Roman numeral to signify the family member. For example, if a man's name is Paul Jones and his father and grandfather were also named Paul, that would make him Paul Jones III. Royal families also use this system. 

How Roman Numerals Are Made

To write Roman numerals, we use seven letters of the alphabet. The letters, which are always capitalized, are I, V, X, L, C, D, and M. The table below illustrates the value for each of these numerals.

Roman Numeral Symbols

I one
V five
X ten
L fifty
C one hundred
D five hundred
M one thousand

Roman numerals are arranged and combined in a specific order to represent numbers. Numerals (their values) are added together when written in groups, so XX = 20 (because 10+10 = 20). However, one cannot put more than three of the same numerals together. In other words, one can write III for three, but can't use IIII. Instead, four is indicated with IV.

If a letter with a smaller value is placed before a letter with a larger value, one subtracts the smaller from the larger. For example, IX = 9 because one subtracts 1 from 10. It works the same way if a smaller number comes after a larger number, only one adds to it. For instance, XI = 11 because X = 10 and I = 1, and 10+1=11.

50 Roman Numerals

The following list of 50 Roman numerals will help you learn how they are created.

  • Numerals 1 to 10:
    • 1 = I
    • 2 = II
    • 3 = III
    • 4 = IV
    • 5 = V
    • 6 = VI
    • 7 = VII
    • 8 = VIII
    • 9 = IX
    • 10 = X
  • Numerals 11 to 20:
    • 11 = XI
    • 12 = XII
    • 13 = XIII
    • 14 = XIV
    • 15 = XV
    • 16 = XVI
    • 17 = XVII
    • 18 = XVIII
    • 19 = XIX
    • 20 = XX
  • Numerals 30 to 50:
    • 30 = XXX
    • 40 = XL
    • 50 = L

How to Memorize Roman Numerals

Sometimes, using a different writing method can be tricky and you won't always remember which Roman numeral you need to use. As long as you understand the explanations above and recollect the simple overview in the table, with some practice, you'll master the Roman numerals in no time.

One additional method to anchor these different types of numbers in your memory is to use a mnemonic and put the letters into a more memorable sentence.

For example:

I Value Xylophones Like Cows Do Milk

Or in reverse:

My Dear Cat Loves Xtra Vitamins Intensely

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Your Citation
Fleming, Grace. "When and How to Write Roman Numerals." ThoughtCo, Feb. 16, 2021, thoughtco.com/roman-numerals-1857217. Fleming, Grace. (2021, February 16). When and How to Write Roman Numerals. Retrieved from https://www.thoughtco.com/roman-numerals-1857217 Fleming, Grace. "When and How to Write Roman Numerals." ThoughtCo. https://www.thoughtco.com/roman-numerals-1857217 (accessed December 8, 2022).