Reading the numbers MMDCCLXVII was not difficult for the ancient Romans or for the many medieval Europeans who continued to use the Roman system. Learn how to read roman numerals by following a few basic rules.
Step
Method 1 of 3: Reading Roman Numerals
Step 1. Learn the basic value of each number
There are only a few roman numerals, so they can be learned quickly:
- I = 1
- V = 5
- X = 10
- L = 50
- C = 100
- D = 500
- M = 1000
Step 2. Use the donkey bridge
Donkey's bridge is a phrase that can be remembered more easily than a series of numbers, so it can help you remember the sequence of roman numerals. Try saying the following phrase to yourself ten times:
I Valu Xylophones Like Cows Do Milk.
Step 3. Add up the digits in the number starting with the larger number
If the numbers are arranged from largest to smallest, all you have to do to read the number is add up the values of each number. Here are some examples:
- VI = 5 + 1 = 6
- LXI = 50 + 10 + 1 = 61
- III = 1 + 1 + 1 = 3
Step 4. Subtract the number from the number starting with a smaller number
Most people who use roman numerals save space by using subtraction to represent specific numbers. Subtraction occurs when the smaller number is in front of the larger number. This rule only occurs in a few situations:
- IV = 1 subtracted from 5 = 5 - 1 = 4
- IX = 1 subtracted from 10 = 10 - 1 = 9
- XL = 10 subtracted from 50 = 50 - 10 = 40
- XC = 10 subtracted from 100 = 100 - 10 = 90
- CM = 100 subtracted from 1000 = 1000 - 100 = 900
Step 5. Split a number into parts to make it easier
If necessary, divide a number into groups of numbers to make it easier. Always make sure you recognize all the "subtraction problems" that occur when the smaller number is in front of the larger number, and combine the two numbers into one group.
- Example: try reading DCCXCIX.
- There are two places in a number that start with a smaller number: XC and IX.
- Combine the numbers that must use the "rule of subtraction" into one group, and separate the other numbers: D + C + C + XC + IX.
- Translate into regular numbers, and use the subtraction rule if necessary: 500 + 100 + 100 + 90 + 9
- Add up all the numbers: DCCXCIX = 799.
Step 6. Notice the horizontal line on the very large number
If there is a horizontal line above a number, multiply the number by 1,000. However, be careful: many people put horizontal lines above and below each roman numeral, just for decoration.
- Example: number X with " –" above it means 10,000.
- If you're not sure if the horizontal lines are just decoration, take a look at the context. Is it normal for a general to send as many as 10 soldiers, or 10,000 people? Is it reasonable for a recipe to use 5 apples, or 5,000 apples?
Method 2 of 3: Example
Step 1. Count from one to ten
This is a good set of numbers to learn. If there are two choices, then there are two correct ways to write the number. Most people choose only one way, using the subtraction method whenever possible, or writing all numbers as additions.
- 1 = I
- 2 = II
- 3 = III
- 4 = IV or IIII
- 5 = V
- 6 = VI
- 7 = VII
- 8 = VIII
- 9 = IX or VIII
- 10 = X
Step 2. Count multiples of ten
The following are roman numerals from ten to one hundred, calculated by multiples of ten:
- 10 = X
- 20 = XX
- 30 = XXX
- 40 = XL or XXXX
- 50 = L
- 60 = LX
- 70 = LXX
- 80 = LXXX
- 90 = XC or LXXXX
- 100 = C
Step 3. Challenge yourself with more difficult numbers
Here are some of the more difficult challenges. Try to count yourself, then highlight the answers to make it appear:
- LXXVII = 77
- XCIV = 94
- DLI = 551
- MCMXLIX = 1,949
Step 4. Read the year
The next time you watch a movie, look for the year written in Roman numerals at the beginning of the film. Divide numbers into groups for easy reading:
- MCM = 1900
- MCM L = 1950
- MCM LXXX V = 1985
- MCM XC = 1990
- MM = 2000
- MM VI = 2006
Method 3 of 3: Reading Uncommon Ancient Texts
Step 1. Use this section for ancient texts only
Roman numerals were not standardized until the modern age. Even the Romans themselves did not use roman numerals consistently, and various variations were used well into the Middle Ages, and even into the 19th and early 20th centuries. If you come across ancient text with roman numerals that don't make sense when read in the usual system, use the following steps to help read the numbers.
If it's your first time learning roman numerals, skip this section
Step 2. Read the unusual repetition
Most modern people don't like to repeat the same number when they can, and never subtract more than one number at a time. Ancient sources do not follow these rules, but they are usually easy to understand. Example:
- VV = 5 + 5 = 10
- XXC = (10 + 10) subtracted from 100 = 100 - 20 = 80
Step 3. Pay attention to the multiplication sign
Oddly enough, ancient texts sometimes used a smaller number in front of a larger number to signify multiplication, not subtraction. For example, VM could mean 5 x 1,000 = 5,000. There's not always an easy way to tell when it happened, but sometimes numbers are written a little differently:
- The dot between two numbers: VI. C = 6 x 100 = 600.
- Numbers written in small above: IVM = 4 x 1,000 = 4,000.
Step 4. Understand variation I
In ancient texts, the symbol j or J was sometimes used, instead of i or I, at the end of a number. Even less often, the extra large I at the end of the number can signify 2 instead of 1.
- Example: xvi or xvj both mean 16.
- xvI = 10 + 5 + 2 = 17
Step 5. Read large numbers with unusual symbols
Early printers sometimes used a symbol called an apostrophus, which is similar to an inverted C or symbol). These symbols and their variations are used only for large numbers:
- M is sometimes written CI) or by early printers, or in ancient Rome.
- D is sometimes written I)
- Writing the above numbers in additional (and) symbols expresses the meaning of multiplying by 10. Example: (CI)) = 10,000 and ((CI))) = 100,000.
Tips
- Even though the Romans didn't have lowercase letters, you can use lowercase letters to write roman numerals.
-
Only the “subtraction rule” situations listed above apply. Roman numerals do not use subtraction in all other situations:
- V, L, and D are never subtracted, only added. Write 15 as XV instead of XVX.
- Only one number can be deducted at a time. Write 8 as VIII, not IIX.
- Do not use subtraction if one number is more than ten times greater than another number. Write 99 as LXCIX, not IC.
