Welcome to Roman Numerals Ready to start? Click on an activity or scroll down for useful infomation The values I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1000 The basic rules If a symbol appears after a larger or equal symbol it is added. eg VI = 6 If a symbol appears before a larger symbol it is subtracted eg IV = 4 The same symbol cannot be used more than 3 times in a row I is only subtracted from V and X, X is only subtracted from L and C, C is only subtracted from D or M Convert numbers to numerals Example. 1984. First break down into unit parts 1000, 900, 80, 4 1000 = M, 900 = CM, 80 = LXXX, 4 = IV Join back together to give MCMLXXXIV Convert numerals to numbers Example. MCMXCVII. Working from left, break down into components when find smaller symbol M, CM, XC, V, II M = 1000, CM = 900, XC = 90, V = 5, II =2 Add values to get 1997 Adding numerals The problem is handing subtraction pair, eg IV, so have to break rules and IV becomes IIII Example. CLXXIV + XXXIX. This converts to CLXXIIII + XXXVIIII Combine the two and place in order largest to smallest. This gives CLXXXXXVIIIIIIII Consolidate like values. eg IIIII becomes V. This gives CLLVVIII Repeat until fully consolidated. This gives CCXIII Subtracting numerals The problem is handing subtraction pair, eg XC, so have to break rules and XC becomes LXXXX Example. CLXXIV – XXXIX. This converts to CLXXIIII – XXXVIIII Cross out matching symbols either side of the minus sign. eg XX appears on both sides This gives CL – XV Find largest value on right, eg X. Then find a larger value on left, eg L. Break this value down to a value that contain the chosen value on right. This gives CXXXXX – XV Repeat crossing out and break down steps until right side is empty. This gives CXXXV
