Desimalform

Desimalform, or decimal form, is the base-10 representation of numbers using digits 0 through 9 and a decimal separator to distinguish integer and fractional parts. In decimal form, the value of each digit depends on its position relative to the separator: digits to the left are multiplied by powers of 10, while digits to the right are multiplied by negative powers of 10. The decimal separator is commonly a point in English-language contexts, while some regions use a comma.

Every decimal representation corresponds to a real number, with terminating and repeating decimals being the two common forms for rationals. Terminating decimals end after a finite number of digits—for example, 0.5 or 2.75. Repeating decimals continue forever with a repeating block, like 0.333... or 1.666.... In mathematical notation, recurring digits may be indicated with a bar over the repeating portion or with parentheses.

Rational numbers have decimal expansions that terminate or repeat; irrational numbers have nonterminating, nonrepeating decimals, such as √2 ≈ 1.41421356…. Decimals are used to express measurements, money, probabilities, and other quantitative data, and they allow straightforward comparison and arithmetic when aligned by the decimal point.

In computing and data processing, decimals can be stored exactly as decimal strings or approximately with fixed- or floating-point representations. Decimals appear in scientific notation and currency formats, and locale differences may affect the symbol used for the decimal separator.