decimaltal

A decimaltal is a number written in decimal notation (base-10). It consists of an integer part and a fractional part, separated by a decimal separator, which is a point in many English-language contexts and a comma in many European locales. Examples include 123.45 and 0.007.

In the decimal system, each digit represents a power of ten according to its position: ..., 10^2, 10^1, 10^0, 10^{-1}, 10^{-2}, and so on. The digits 0 through 9 are used.

Finite decimal numbers have a limited number of digits after the separator. They correspond to fractions whose reduced denominator has only factors 2 and 5, i.e., denominators that divide a power of ten.

Repeating decimals have an infinite, repeating tail. They arise from fractions whose denominators contain prime factors other than 2 and 5, for example 1/3 = 0.333... and 2/7 = 0.285714285714...

Decimaltal are widely used in everyday arithmetic, finance, science, and education. In computing, decimal arithmetic can be implemented with fixed-point or floating-point representations; some programming languages offer exact decimal types to improve financial accuracy.

Locale conventions vary: the decimal separator can be a dot or a comma depending on language and region.

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