This article is classified "Real"
Roman Numerals are an ancient way of numbering, involving different
symbols, and a slightly different principal from our usual decimal manner.
The following key symbols are used:
* I = 1
* V = 5
* X = 10
* L = 50
* C = 100
* D = 500
* M = 1000
They are combined together to form a string, where the progressively
decreasing numbers are added together to form a total. Numbers are
generally expressed in descending order, except where the number you wish
to express (say 9) is next to the relevant number above (10), in which case
they are expressed in terms of number minus number (10 - 1) [1]. Note that
only one alteration symbol is allowed, so 8 cannot be represented by "IIX".
The following is an example of using symbols out of order:
* CM = (100)(1000) = 1000-100 = 900
In this way, all numbers can be reproduced (to a point). Here are some
examples:
1) 1997 = MCMXCVII = 1000+(1000-100)+(100-10)+5+1+1 =
1000+900+90+7.
2) 1066 = MLXVI = 1000+50+10+5+1.
3) 414 = CDXIV = (500-100)+10+(5-1) = 400+10+4.
There is no symbol for zero.
[1] Though sometimes numbers are still expressed in the first way, such
as in one representation of 4 ("IIII"), whereas the "normal" is "IV"
(5 - 1).