Zero, in arithmetic, is the name of the digit 0, sometimes called naught or a cypher. It is used to indicate the absence of quantity. A zero is needed in a positional numeral system, such as the familiar decimal system commonly used by most people today. In a positional system, the position, or place, of a digit determines the digit’s value. Thus, in the numeral 246, the digit 2 stands for two hundred, the digit 4 stands for four tens (or forty), and the digit 6 stands for six units, or ones. The numeral represents the number 246. In order to write the number 206, a symbol is needed to show that there are no tens. The digit 0 serves this purpose. Zero added to or subtracted from a number gives the original number. A number multiplied by zero gives zero. Division by zero is undefined. Zero is an even number.
On most scales, zero marks the starting point or the neutral position. Positive numbers are placed to the right or above zero, and negative numbers are placed to the left or below zero. But on some scales, zero is set arbitrarily. For example, on a Celsius thermometer, zero is set at the temperature at which water freezes.
There is evidence that the Maya of Central America were using symbols for zero by about A.D. 250 and that the Hindus had developed such a symbol around the same time. The Indian astronomer Brahmagupta wrote the mathematical text Brahmasphutasiddhanta in 628 A.D. Scholars recognize this as the earliest known work to describe zero as a numerical value. The Hindu symbol spread from India and was adopted in Europe during the late 1400’s. The word zero probably came from ziphirum, a Latinized form of the Arabic word sifr. Sifr is a translation of the Sanskrit word sunya (void or empty).
