Roman Numbers

Numbers and Numerals	Composite Numbers	Prime Numbers	Facts (Prime Numbers)	Even Numbers
Odd Numbers	Natural Numbers	Whole Numbers	Predecessor Number	Successor Number
Number Expansion	Number Comparison	Literal Numbers	Roman Numbers	Coprime Numbers
Perfect Numbers	Multiplication Properties of Numbers	Order of Numbers	Sieve of Eratosthenes	Number line
Square Numbers	Shortcut Method of Numbers	Cube Numbers	Real Numbers

Explanation Roman Numbers are one of the oldest system of writing numerals. This system of writing was developed by Roman people around 2000 years ago. Romans used seven letters of alphabets as basic symbols for writing numerals. These seven alphabets are shown in following table :- Roman alphabets Equivalent Numeric Value I 1 V 5 X 10 L 50 C 100 D 500 m 1000 Read the following points to be kept in mind while writing numbers in Roman System 1). Alphabets I, X, C and M can be repeated and Repetition means addition. For example :- II = 1 + 1 = 2, III = 1 + 1 + 1 = 3 XX = 10 + 10 = 20 , XXX = 10 + 10 + 10 = 30 CC = 100 + 100 = 200, CCC = 100 + 100 + 100 = 300 MM = 1000 + 1000 = 2000, MMM = 1000 + 1000 + 1000 = 3000 Note :- Repetition cannot be more than 3 times. Also Symbols V, L, D cannot be repeated. 2). An alphabet of lesser value written on the left side of an alphabet of greater value is always subtracted from greater value alphabet. For example :- IX = 10 - 1 = 9 CM = 1000 - 100 = 900 IV = 5 - 1 = 4 3). An alphabet of lesser value written on the right side of an alphabet of greater value is always added to greater value alphabet. For example :- XI = 10 + 1 = 11 VI = 5 + 1 = 6 MC = 1000 + 100 = 1100 4). Following are some more tips on subtraction of Roman Numbers. (a) Alphabet I can be subtracted from V and x only :- IV = 5 - 1 = 4 IX = 10 - 1 = 9 (b) Alphabet X can be subtracted from L, M and C only :- XL = 50 - 10 = 40 XM = 1000 - 10 = 990 XC = 100 - 10 = 90 (c) Alphabet C can be subtracted from D and M only :- CD = 500 - 100 = 400 CM = 1000 - 100 = 900 (d) Alphabet V,L and D are never subtracted which means that alphabets V, L and D are never written on the left side of greater value alphabet. (e) When an alphabet of lesser value is placed between two alphabets of greater value, it is always subtracted from alphabet placed on its right side. For Example :- VIV = 5 + (5 - 1) = 5 + 4 = 9 XIV = 10 + (5 - 1) = 10 + 4 = 14