décimales

Décimales are the digits that appear to the right of the decimal separator in a base-10 representation of a number. The separator itself—point or comma depending on locale—divides the integer part from the fractional part.

Each digit to the right of the separator represents a negative power of ten: tenths (1/10), hundredths (1/100), thousandths (1/1000), and so on.

Decimal expansions can terminate after a finite number of digits, such as 3.14 or 0.75. They can also be infinite: if the digits eventually repeat a fixed block, the decimal is recurring (for example, 0.333...). If the expansion never repeats, the number is irrational.

Decimals arise from dividing integers by powers of ten and can be converted to fractions by multiplying by the appropriate power of ten. Conversely, fractions with denominators that are powers of ten become terminating decimals.

Décimales are central to measurement, finance, statistics, and computation. They require conventions for rounding and precision and are implemented in hardware and software through fixed-point or floating-point representations, with locale-dependent decimal separators impacting data formatting and parsing.