Numerals are signs or symbols for graphic representation of numbers. The earliest forms of numerical notation were simply groups of straight lines, either vertical or horizontal, each line corresponding to the number 1. Such a system was inconvenient when dealing with large numbers.
The system of number symbols created by the Romans expresses all numbers from 1 to 1,000,000 with the help of seven symbols:
I = 1
V = 5
X = 10
L = 50
C = 100
D = 500
M = 1,000
Roman numerals are read from left to right- The symbols are usually added together. For example:
IV = 4
VI = 6
LX = 60
XL = 40
MMII = 2002
MCMLVII = 1957
A small bar placed over the numeral multiplies the numeral by 1,000.
Thus, theoretically, it is possible, by using an infinite number of bars, to express the numbers from 1 to infinity. In practice, however, one bar is usually used; two are rarely used, and more than two are almost never used.
Roman numerals are still used today, more than 2,000 years after their introduction. The Roman system’s only drawback is that it is not suitable for rapid written calculations.
The Arabic system of numerical notation is used in most parts of the world today. This system was first developed in India in the 3rd century BC. At that time the numerals 1,4, and 6 were written in the same form today.
The important innovation in the Arabic system was the use of positional notation, in which individual number symbols assume different values according to their position in the written numeral. Positional notation is made possible by the use of a symbol for zero. The symbol 0 makes it possible to differentiate between 11, 101, and 1.001 without the use of additional symbols, and all numbers can be expressed in terms of ten symbols, the numerals from 1 to 9 plus 0. Positional notation also greatly simplifies all forms of written numerical calculation.