Reading the number MMDCCLXVII would not have been a problem for an inhabitant of ancient Rome or for many people of the Middle Ages in Europe who continued to use the Roman numeral system. Learn to read these numbers by following some basic rules.
Steps
Method 1 of 3: Read Roman Numerals
Step 1. Learn the basic value of each digit
There are few Roman numerals, so learning them won't take long:
- I = 1
- V = 5
- X = 10
- L = 50
- C = 100
- D = 500
- M = 1000
Step 2. Use a mnemonic technique
Learning a mnemonic phrase is easier than memorizing a list of numbers. It will also help you remember the order of the digits. Try to repeat it several times:
THEor V.oglio Xilophones Lnails C.ome D.to M.anual.
Step 3. Add the numbers with the highest digit first
If the digits are from the largest to the smallest, all you have to do is add their value as you read them. Here are some examples:
- VI = 5 + 1 = 6
- LXI = 50 + 10 + 1 = 61
- III = 1 + 1 + 1 = 3
Step 4. If the first numbers are lower, you have to subtract the digit
To avoid writing excessively long numbers, subtraction is often used. This only happens if the starting figure is lower than the one next to it. This convention is used only in certain situations:
- IV = 1 must be subtracted from 5 = 5 - 1 = 4
- IX = 1 must be subtracted from 10 = 10 - 1 = 9
- XL = 10 must be subtracted from 50 = 50 - 10 = 40
- XC = 10 must be subtracted from 100 = 100 - 10 = 90
- CM = 100 must be subtracted from 1000 = 1000 - 100 = 900
Step 5. To read the number more easily, divide it into several parts
Divide the number into groups of digits to read it more easily. If there are any "subtractions", include the lower figures in front of the higher ones in the same group.
- For example, try reading DCCXCIX.
- The number contains two subtractions: XC and IX.
- Keep the subtraction digits in the same group and divide the remaining ones: D + C + C + XC + IX.
- Translate into ordinary numerals, using subtraction when necessary: 500 + 100 + 100 + 90 + 9
- Add them together: DCCXCIX = 799
Step 6. Pay attention to the segment above the high numbers
If there is a horizontal segment above a number, multiply it by 1000. Be careful, as the segment is often drawn both above and below the Roman numeral, for decorative purposes only.
- For example, the X with " –"plotted above means 10,000.
- If you can't tell if the bar is decorative or not, refer to the context. A general would send 10,000 soldiers and not 10 to war, while in a recipe there could be 5 apples and not 5,000.
Method 2 of 3: Examples
Step 1. Count from one to ten
Here is a list of numbers to learn. If there are two options for a number, it means that both are correct and that they can be chosen either. Use subtraction whenever possible or write all the digits below to add up.
- 1 = I
- 2 = II
- 3 = III
- 4 = IV or IIII
- 5 = V
- 6 = VI
- 7 = VII
- 8 = VIII
- 9 = IX or VIIII
- 10 = X
Step 2. Count from ten onwards
Here are the Roman numerals from 10 to 100, starting from 10:
- 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. Test yourself with the most difficult numbers
Here are some more complex challenges. Try to solve them yourself and then highlight the answer to view it:
- LXXVII = 77
- XCIV = 94
- DLI = 551
- MCMXLIX = 1949
Step 4. Read the dates
The next time you watch a movie, look for dates written in Roman numerals during the opening credits. You can divide them into groups to read them more easily:
- MCM = 1900
- MCM L = 1950
- MCM LXXX V = 1985
- MCM XC = 1990
- MM = 2000
- MM VI = 2006
Method 3 of 3: Read Particular Ancient Texts
Step 1. This section refers only to ancient texts
Roman numerals were not standardized until more modern times. Even the Romans used them inconsistently and all the variations were also employed in the Middle Ages, until the beginning of the twentieth century. If you happen to find a Roman numeral in an ancient text, which doesn't seem to make sense, refer to the following steps to interpret it.
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Step 2. Read the unusual repetitions
According to modern usage, it is necessary to avoid repetitions of the same digit, where possible, and never subtract more than one digit at a time. The old sources did not respect these rules, however it will not be difficult to grasp their meaning. For instance:
- VV = 5 + 5 = 10
- XXC = (10 + 10) must be subtracted from 100 = 100 - 20 = 80
Step 3. Look for any signs of multiplication
At the risk of creating confusion, it is possible to find in ancient texts low figures in front of higher figures as a sign of multiplication and not of subtraction. For example VM could mean 5 x 1000 = 5000. There is no exact way to tell when this convention is in place, but sometimes the number is slightly altered:
- A point between two numbers: VI. C = 6 x 100 = 600.
- A subscription: IVM. = 4 x 1000 = 4000.
Step 4. Learn the variations of I
In old prints, the symbol j or J was sometimes used in place of the i or I at the end of the number. More rarely a longer I at the end of the number could mean 2 instead of 1.
- For example, xvi or xvj both equal 16.
- xvI = 10 + 5 + 2 = 17
Step 5. Read higher numbers with unusual symbols
Older prints sometimes used a symbol called an apostrophe, similar to an upside down C or symbol). This symbol, along with other variations, was used with higher numbers:
- M was sometimes written CI) or ∞ in older prints, or as ϕ in ancient Rome.
- D was written I)
- Enclosing the previous numbers in the symbols (and) indicated multiplication by 10. For example, (CI)) = 10000 and ((CI))) = 100000.
Advice
- Although the Romans didn't have them, you can use lowercase letters to write Roman numerals.
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The Romans used only the subtractions indicated above, all other situations were avoided.
- V, L, and D are never used for subtraction, only for addition. Write 15 like this: XV and not like this XVX.
- Only one digit can be subtracted at a time. Write 8 like this and not like this IIX.
- Don't use subtraction if one digit is 10 times higher than the other. Write 99 so LXCIX and not so IC.
