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The Eastern Arabic numerals, also called Indo-Arabic numerals, are the symbols used to represent numerical digits in conjunction with the Arabic alphabet in the countries of the Mashriq (the east of the Arab world), the Arabian Peninsula, and its variant in other countries that use the Persian numerals on the Iranian plateau and in Asia.
The early Hindu–Arabic numeral system used a variety of shapes. [1] It is unknown when the Western Arabic numeral shapes diverged from those of Eastern Arabic numerals; it is considered that 1, 2, 3, 4, 5, and 9 are related in both versions, but 6, 7 and 8 are from different sources. [2]
The numeral system originates from an ancient Indian numeral system, which was re-introduced during the Islamic Golden Age in the book On the Calculation with Hindic Numerals written by the Persian mathematician and engineer al-Khwarizmi, whose name was Latinized as Algoritmi. [note 1]
These numbers are known as ʾarqām hindiyyah (أَرْقَام هِنْدِيَّة) in Arabic. They are sometimes also called Indic numerals [3] or Arabic–Indic numerals [4] in English. However, that is sometimes discouraged as it can lead to confusion with Indian numerals, used in Brahmic scripts of the Indian subcontinent. [5]
Each numeral in the Persian variant has a different Unicode point even if it looks identical to the Eastern Arabic numeral counterpart. [6] However, the variants used with Urdu, Sindhi, and other Languages of South Asia are not encoded separately from the Persian variants.
Western Arabic | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
Eastern Arabic [lower-alpha 1] | ٠ | ١ | ٢ | ٣ | ٤ | ٥ | ٦ | ٧ | ٨ | ٩ | ١٠ |
Persian [lower-alpha 2] | ۴ | ۵ | ۶ | ||||||||
Urdu [lower-alpha 3] | ۴ | ۶ | ۷ | ||||||||
Abjad numerals | ب | جـ | د | هـ | و | ز | حـ | ط | ى |
Written numerals are arranged with their lowest-value digit to the right, with higher value positions added to the left. That is identical to the arrangement used for Western Arabic numerals, even though Arabic script is read from right-to-left. [7] Columns of numbers are usually arranged with the decimal points aligned.
Negative signs are written to the right of magnitudes, e.g. −٣ (−3).
In-line fractions are written with the numerator on the left and the denominator on the right of the fraction slash, e.g. ٢/٧ (2⁄7).
The Arabic decimal separator ٫ (U+066B) or the comma , is used as the decimal mark, as in ٣٫١٤١٥٩٢٦٥٣٥٨ (3.14159265358).
The arabic thousands separator ٬ (U+066C) or quote ' or Arabic comma ، (U+060C) may be used as a thousands separator, e.g. ١٬٠٠٠٬٠٠٠٬٠٠٠ (1,000,000,000).
Eastern Arabic numerals are in predominant use over Western Arabic numerals in many countries to the east of the Arab world, notably Iran and Afghanistan.
In Arabic-speaking Asia, as well as Egypt and Sudan, both types of numerals are in use (and are often employed alongside each other), though Western Arabic numerals are increasingly used, including in Saudi Arabia. The United Arab Emirates uses both Eastern and Western Arabic numerals.
In Pakistan, Western Arabic numerals are more extensively used digitally. Eastern numerals continue to see use in Urdu publications and newspapers, as well as signboards.[ clarification needed ]
In the Maghreb, only Western Arabic numerals are commonly used. In medieval times, these areas used a slightly different set (from which, via Italy, Western Arabic numerals derive).
The Thaana writing system used for the Maldivian language adopted its first nine letters (haa, shaviyani, noonu, raa, baa, lhaviyani, kaafu, alifu, and vaavu) from Perso-Arabic digits. [8]
The ten Arabic numerals 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9 are the most commonly used symbols for writing numbers. The term often also implies a positional notation using the numerals, as well as the use of a decimal base, in particular when contrasted with other systems such as Roman numerals. However, the symbols are also used to write numbers in other bases such as octal, as well as for writing non-numerical information such as trademarks or license plate identifiers.
The Arabic alphabet, or the Arabic abjad, is the Arabic script as specifically codified for writing the Arabic language. It is written from right-to-left in a cursive style, and includes 28 letters, of which most have contextual letterforms. The Arabic alphabet is considered an abjad, with only consonants required to be written; due to its optional use of diacritics to notate vowels, it is considered an impure abjad.
A bidirectional text contains two text directionalities, right-to-left (RTL) and left-to-right (LTR). It generally involves text containing different types of alphabets, but may also refer to boustrophedon, which is changing text direction in each row.
The decimal numeral system is the standard system for denoting integer and non-integer numbers. It is the extension to non-integer numbers of the Hindu–Arabic numeral system. The way of denoting numbers in the decimal system is often referred to as decimal notation.
A numeral system is a writing system for expressing numbers; that is, a mathematical notation for representing numbers of a given set, using digits or other symbols in a consistent manner.
Thaana, Tãnaa, Taana or Tāna is the present writing system of the Maldivian language spoken in the Maldives. Thaana has characteristics of both an abugida and a true alphabet, with consonants derived from indigenous and Arabic numerals, and vowels derived from the vowel diacritics of the Arabic abjad. Maldivian orthography in Thaana is largely phonemic.
A decimal separator is a symbol that separates the integer part from the fractional part of a number written in decimal form. Different countries officially designate different symbols for use as the separator. The choice of symbol also affects the choice of symbol for the thousands separator used in digit grouping.
Science in the medieval Islamic world was the science developed and practised during the Islamic Golden Age under the Abbasid Caliphate of Baghdad, the Umayyads of Córdoba, the Abbadids of Seville, the Samanids, the Ziyarids and the Buyids in Persia and beyond, spanning the period roughly between 786 and 1258. Islamic scientific achievements encompassed a wide range of subject areas, especially astronomy, mathematics, and medicine. Other subjects of scientific inquiry included alchemy and chemistry, botany and agronomy, geography and cartography, ophthalmology, pharmacology, physics, and zoology.
A numerical digit or numeral is a single symbol used alone or in combinations, to represent numbers in a positional numeral system. The name "digit" comes from the fact that the ten digits of the hands correspond to the ten symbols of the common base 10 numeral system, i.e. the decimal digits.
Algorism is the technique of performing basic arithmetic by writing numbers in place value form and applying a set of memorized rules and facts to the digits. One who practices algorism is known as an algorist. This positional notation system has largely superseded earlier calculation systems that used a different set of symbols for each numerical magnitude, such as Roman numerals, and in some cases required a device such as an abacus.
Muhammad ibn Musa al-Khwarizmi, or simply al-Khwarizmi, was a Khwarazm-born polymath who produced vastly influential Arabic-language works in mathematics, astronomy, and geography. Around 820 CE, he was appointed as the astronomer and head of the House of Wisdom in Baghdad, the contemporary capital city of the Abbasid Caliphate.
The Indian numbering system is used in the Indian subcontinent to express large numbers. The terms lakh or 1,00,000 and crore or 1,00,00,000 are the most commonly used terms in Indian English to express large numbers in the system.
The Persian alphabet, also known as the Perso-Arabic script, is the right-to-left alphabet used for the Persian language. It is a variation of the Arabic script with five additional letters: پ چ ژ گ, in addition to the obsolete ڤ that was used for the sound. This letter is no longer used in Persian, as the -sound changed to, e.g. archaic زڤان > زبان 'language'.
Mathematics during the Golden Age of Islam, especially during the 9th and 10th centuries, was built upon syntheses of Greek mathematics and Indian mathematics. Important developments of the period include extension of the place-value system to include decimal fractions, the systematised study of algebra and advances in geometry and trigonometry.
The Hindu–Arabic numeral system is a positional base ten numeral system for representing integers; its extension to non-integers is the decimal numeral system, which is presently the most common numeral system.
In Unicode and the UCS, a compatibility character is a character that is encoded solely to maintain round-trip convertibility with other, often older, standards. As the Unicode Glossary says:
A character that would not have been encoded except for compatibility and round-trip convertibility with other standards
A numeral is a character that denotes a number. The decimal number digits 0–9 are used widely in various writing systems throughout the world, however the graphemes representing the decimal digits differ widely. Therefore Unicode includes 22 different sets of graphemes for the decimal digits, and also various decimal points, thousands separators, negative signs, etc. Unicode also includes several non-decimal numerals such as Aegean numerals, Roman numerals, counting rod numerals, Mayan numerals, Cuneiform numerals and ancient Greek numerals. There is also a large number of typographical variations of the Western Arabic numerals provided for specialized mathematical use and for compatibility with earlier character sets, such as ² or ②, and composite characters such as ½.
Modern Arabic mathematical notation is a mathematical notation based on the Arabic script, used especially at pre-university levels of education. Its form is mostly derived from Western notation, but has some notable features that set it apart from its Western counterpart. The most remarkable of those features is the fact that it is written from right to left following the normal direction of the Arabic script. Other differences include the replacement of the Greek and Latin alphabet letters for symbols with Arabic letters and the use of Arabic names for functions and relations.
Many scripts in Unicode, such as Arabic, have special orthographic rules that require certain combinations of letterforms to be combined into special ligature forms. In English, the common ampersand (&) developed from a ligature in which the handwritten Latin letters e and t were combined. The rules governing ligature formation in Arabic can be quite complex, requiring special script-shaping technologies such as the Arabic Calligraphic Engine by Thomas Milo's DecoType.
This leads to the question of the shape of the nine numerals. Still after the year 1000 al-Biruni reports that the numerals used in India had a variety of shapes and that the Arabs chose among them what appeared to them most useful. And al-Nasawi (early eleventh century) in his al-Muqni' fi l-hisåb al-hindi writes at the beginning, when describing the forms of the nine signs, "Les personnes qui se sont occupées de la science du calcul n'ont pas été d'accord sur une partie des formes de ces neuf signes; mais la plupart d'entre elles sont convenues de les former comme il suit" (then follow the common Eastern Arabic forms of the numerals). Among the early arithmetical writings that are edited al-Baghdådi mentions that for 2, 3, and 8 the Iraqis would use different forms. This seems to be corroborated by the situation in the Sijzi manuscript. Further, the Latin adaptation of al-Khwårizmi's book says that 5, 6, 7, and 8 may be written differently. If this sentence belongs to al-Khwårizmi's original text, that would be astonishing. Rather one would be inclined to assume that this is a later addition made either by Spanish-Muslim redactors of the Arabic text or by the Latin translator or one of the adapters of the Latin translation, because it is in these four signs (or rather, in three of them) that the Western Arabic numerals differ from the Eastern Arabic ones.
That the Eastern Arabic numerals were also known in al-Andalus is demonstrated by several Latin manuscripts that clearly show the Eastern forms… Unfortunately, the documentary evidence on the side of Western Arabic numerals is extremely poor. So far, the oldest specimen of Western Arabic numerals that became known to me occurs in an anonymous treatise on automatic water-wheels and similar devices in MS Florence… dated to 1265 and 1266… Here we have the symbols for 1, 2, 3, 4, 5, 8, and 9. The figures for 2 and 3 look like the corresponding Eastern Arabic forms and are not turned by 90o as in other, more recent, Maghrebi documents… When one compares the Eastern and the Western Arabic forms of the numerals, one finds that they are not completely different. The Western forms of 1, 2, 3, 4, 5, and 9 can be recognized as being related to, or derived from, the corresponding Eastern forms. Major difficulty arises with 6, 7, and 8. It may not be accidental that the oldest existing Latin re-working made from the translation of al-Khwårizmi's Arithmetic mentions just these three figures (plus 5) as being differently written. As I have already said earlier, this notice can hardly stem from al-Khwårizmi himself; rather it may have been added by a Spanish-Arabic redactor of al-Khwårizmi's text. He would have been best equipped to recognize this difference. The Latin translator, or Latin adapters, would less probably have been able to notice the difference between the Eastern and Western Arabic forms of these four numerals. We cannot explain why, and how, the three Western figures were formed, especially since we have no written specimens of Western Arabic numerals before the thirteenth century.