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Roman Numerals

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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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