Roman Numerals

The numeric system known today as Roman Numerals utilizes only seven symbols, which are added and subtracted to form any number. A superscript bar over a number multiplies it by 1,000, and two vertical lines in addition to the superscript bar multiply a number by 100,000. Thus the common symbols are:

I = 1 V = 5 X = 10 L = 50 C = 100 D = 500 M = 1,000

= 5,000 = 10,000 = 50,000 = 100,000 = 500,000 = 1,000,000

= 1,000,000 = 10,000,000 = 100,000,000 = 16,000 etc. = 1,600,000 etc.

There was no symbol for zero

The rule is that when two figures are side by side, if the smaller is on the right, it is added to the larger, and if it is on the left, it is subtracted from the larger. So, VI = 6 and IV = 4. Exceptions to this rule are very rare.

Modern rules have also been added, and are that:

• No more than three of the same symbol can be repeated in a row, and V and L are never repeated.
• The smaller number preceeding a larger number cannot be more than two values lower than the other or be one-half of it. This leaves IV, IX, VL, XL, XC, LD, CD, and CM as the normal pairings, so we will most likely see 1999 written as MCMXCIX rather than MIM.

In reality, these rules were never followed by the Romans. To start, they used more than these seven symbols, and M was used only as an abbreviation of mille or milia, not used in combination with other symbols until the 15^th century. Repetitions of numbers often exceeded the rule of three, but V and L were never repeated. Values including VIIII and even XXXXXX were common. The following table shows how much the symbols vary.

1. I	14. XIV	90. XC or LXXXX
2. II	15. XV	100. C
3. III	16. XVI	200. CC
4. IIII or IV	17. XVII	300. CCC
5. V	18. XVIII or XIIX	400. CCCC or C
6. VI or	19. XIX or XVIIII	500. D or I or
7. VII	20. XX	600. I C
8. VIII or IIX	30. XXX	700. I CC
9. VIIII or IX	40. XL or XXXX	800. I CCC
10. X	50. L	900. I CCCC
11. XI	60. LX	1,000. CI or M or or
12. XII	70. LXX	10,000. CCI or
13. XIII	80. LXXX or XXC	100,000. CCCI or
		500,000. Q