Roman Numerals
Roman numerals are combinations of the seven letters
- I = 1
- V = 5
- X = 10
- L = 50
- C = 100
- D = 500
- M = 1000
Roman numbers are expressed by adding or subtracting combinations of the number values of the letters.
- smaller numbers before larger numbers are subtracted
- smaller number after larger numbers are added
Note that Roman numerals are without zero.
Large numbers are indicated with horizontal lines above them. With a horizontal line the number should be multiplied by 1000.
Example - the Roman number 51
- LI => 50 + 1 = 51
Example - the Roman number 9
- IX => -1 + 10 = 9
Example - Years
- MCMLXXXII => 1000 + (-100 + 1000) + 50 + 10 + 10 + 10 + 1 + 1 = 1982
- MCMLXXVII => 1977
Example - Large Roman Numbers
- V => 5 x 1000 = 5000
Example - some common Roman numbers
- 1 = I
- 2 = II
- 3 = III
- 4 = IV
- 5 = V
- 6 = VI
- 7 = VII
- 8 = VIII
- 9 = IX
- 10 = X
- 11 = XI
- 12 = XII
- 13 = XIII
- 14 = XIV
- 15 = XV
- 16 = XVI
- 17 = XVII
- 18 = XVIII
- 19 = XIX
- 20 = XX
- 30 = XXX
- 40 = XL
- 50 = L
- 60 = LX
- 70 = LXX
- 80 = LXXX
- 90 = XC
- 100 = C
- 150 = CL
- 200 = CC
- 300 = CCC
- 400 = CD
- 500 = D
- 600 = DC
- 700 = DCC
- 800 = DCCC
- 900 = CM
- 1000 = M
- 1600 = MDC
- 1700 = MDCC
- 1900 = MCM
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