ABSTRACT
Zero, or nothing, is a very valuable symbol because it made possible a place-value notation. The ancient Greeks, Romans and Hebrews had letters for numbers; and while they could no doubt perform rapid calculations on an abacus, simple arithmetic would have been very clumsy, and one could worry about numbers too big to be expressed because letters would have run out. The Hindus seem to have invented the numbers we call Arabic, in which the value of a number depends on its place; the figure 2 may represent hundreds, tens or units for example. Having a symbol for zero is essential in such a system for writing 20, 202 and so on; and it is then easy to see how the Arabic numbers superseded the Roman ones.
