Zero is a unique number, belonging to neither the positive nor negative number set. It was the very last number symbol to be developed. Among the ancient Babylonian civilizations of 600 b.c. and earlier, a space was sometimes used to indicate an "empty place," however often as not, spaces were not used. Therefore, using Akkadian symbols and the Babylonia base of sixty, the numbers 1, 60, 3600, and 216,000 were all written with the same symbol. Despite its potential for confusion, the method appears to have been acceptable for several centuries. Around 300 b.c. the Babylonians invented a special sign to serve as a placeholder where a numeral was missing. However, this symbol was apparently used only for intermediate empty positions, so the Babylonians never achieved an absolute positional number system.

The first zero symbol was believed to have originated in the fourth century b.c. by an unknown Indian mathematician. Wanting...