Roman numerals

Roman numerals are a numeral system that was used by ancient Rome. Numbers in this system use letters from the Latin alphabet. Currently, it uses seven symbols:^[1]

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

The Europeans still used Roman numerals even after the fall of the Roman Empire. From the 14th century, the Europeans replaced Roman numerals with Arabic numerals. However, people still use Roman numerals to this day.

One place in which they are sometimes seen is on clock faces (the front of a clock). For example, on the clock of Big Ben, the hours from 1 to 12 are written as:

I, II, III, IV, V, VI, VII, VIII, IX, X, XI, XII

The IV and IX can be read as "one less than 5" (4) and "one less than 10" (9). On many clocks that use Roman numerals, however, 4 is written as IIII.^[2]

1. ↑ Gordon, Arthur E. (1982). Illustrated Introduction to Latin Epigraphy. Berkeley: University of California Press. ISBN 0-520-05079-7. Alphabetic symbols for larger numbers, such as Q for 500,000, have also been used to various degrees of standardization.
2. ↑ "The Mathematical Tourist : IIII versus IV on Clocks". Ivars Peterson. 4 August 2010. Retrieved 31 May 2019. Expressed as Roman numerals, the first twelve numbers are usually given as I, II, III, IV, V, VI, VII, VIII, IX, X, XI, XII. However, on many clock faces, when the numbers on the dial are in Roman numerals, IIII replaces IV.