Roman NumeralsDate: 01/13/97 at 11:34:45 From: Robert Subject: MCMLXXXVI I am trying to learn how to read Roman Numerals. What does MCMLXXXVI mean? Robert Date: 01/13/97 at 12:35:12 From: Doctor Rob Subject: Re: MCMLXXXVI Dear Robert - First you need to know the values of the letters, and then you need to know what the positions of the letters mean. Values: I 1 V 5 X 10 L 50 C 100 D 500 M 1000 _ V 5000 When a letter is repeated one, two, or three times, add up the value that many times. XXX = 10 + 10 + 10 = 30. MM = 2000. V, L, and D cannot be repeated. I, X, C, and M can be repeated up to 3 times. If you want to repeat a letter 4 times, instead use that letter preceding one of the two next larger values: For 4, don't use IIII, but instead IV (I subtracted from V). For 9, don't use VIIII or VIV, but instead IX (I subtracted from X). Similar rules apply for 40, 90, 400, 900. Write the resulting groups in descending order. 794 = 500 + 200 + 90 + 4 = D + CC + XC + IV = DCCXCIV Note that this only works up to 3999. For larger numbers, more letters would have to be assigned the values of 5000, 10000, and so on. To read a numeral, reverse this process. Start at the left, and read off groups which either consist of repetitions of a single letter, or one of the groups IV, IX, XL, XC, CD, CM (representing 4, 9, 40, 90, 400, or 900, respectively). You can recognize when these groups occur because the letters are not in descending order. Add up the values of those groups. MCMLXXXVI = M + CM + L + XXX + V + I = 1000 + 900 + 50 + 30 + 5 + 1 = 1986 I hope this helps. -Doctor Rob, The Math Forum Check out our web site! http://mathforum.org/dr.math/ |
Search the Dr. Math Library: |
[Privacy Policy] [Terms of Use]
Ask Dr. Math^{TM}
© 1994-2015 The Math Forum
http://mathforum.org/dr.math/