In France, the full stop was already in use in printing to make Roman numerals more readable, so the comma was chosen. Tables of logarithms prepared by John Napier in 16 used the period (full stop) as the decimal separator, which was then adopted by Henry Briggs in his influential 17th century work. Fibonacci followed this convention when writing numbers, such as in his influential work Liber Abaci in the 13th century. Gerbert of Aurillac marked triples of columns with an arc (called a "Pythagorean arc"), when using his Hindu–Arabic numeral-based abacus in the 10th century. His Compendious Book on Calculation by Completion and Balancing presented the first systematic solution of linear and quadratic equations in Arabic. The practice is ultimately derived from the decimal Hindu–Arabic numeral system used in Indian mathematics, and popularized by the Persian mathematician Al-Khwarizmi, when Latin translation of his work on the Indian numerals introduced the decimal positional number system to the Western world. Positional decimal fractions appear for the first time in a book by the Arab mathematician Abu'l-Hasan al-Uqlidisi written in the 10th century. When this character was typeset, it was convenient to use the existing comma (99 ,95) or full stop (99. 99 ˌ95), while an L-shaped or vertical bar (|) served as the separatrix in England. Later, a "separatrix" (i.e., a short, roughly vertical ink stroke) between the units and tenths position became the norm among Arab mathematicians (e.g. A similar notation remains in common use as an underbar to superscript digits, especially for monetary values without a decimal separator, as in 99 95. In the Middle Ages, from the original Indian decimal writing, before printing, a bar ( ¯ ) over the units digit was used to separate the integral part of a number from its fractional part, as in 9 995 (meaning 99.95 in decimal point format). 4 Influence of calculators and computers.
In mathematics, the decimal separator is a type of radix point, a term that also applies to number systems with bases other than ten.
In some specialized contexts, the word decimal is instead used for this purpose (such as in International Civil Aviation Organization-regulated air traffic control communications). In many contexts, when a number is spoken, the function of the separator is assumed by the spoken name of the symbol: comma or point in most cases. Symbol-specific names are also used decimal point and decimal comma refer to an (either baseline or middle) dot and comma respectively, when it is used as a decimal separator these are the usual terms used in English, with the aforementioned generic terms reserved for abstract usage. The choice of symbol also affects the choice of symbol for the thousands separator used in digit grouping.Īny such symbol can be called a decimal mark, decimal marker, or decimal sign.
Different countries officially designate different symbols for use as the separator. Three ways to group the number ten thousand with digit group separators.ġ) Space, the internationally recommended thousands separator.Ģ) Period (or full stop), the thousands separator used in many non-English speaking countries.ģ) Comma, the thousands separator used in most English-speaking countries.Ī decimal separator is a symbol used to separate the integer part from the fractional part of a number written in decimal form (e.g., "." in 12.45). Signed-digit representation ( balanced ternary).