Eastern Arabic numerals

(Redirected from Indo-Arabic numerals)
Eastern Arabic numerals on a clock in the Cairo Metro

The Eastern Arabic numerals, also called Arabic-Indic numerals or 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.

Origin

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]

Other names

These numbers are known as ʾarqām hindiyyah (أَرْقَام هِنْدِيَّة) in Arabic. They are sometimes also called Indic numerals[1] or Arabic-Indic numerals[2] in English. However, that is sometimes discouraged as it can lead to confusion with Indian numerals, used in Brahmic scripts of the Indian subcontinent.[3]

Numerals

Each numeral in the Persian variant has a different Unicode point even if it looks identical to the Eastern Arabic numeral counterpart. 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[a] ٠ ١ ٢ ٣ ٤ ٥ ٦ ٧ ٨ ٩ ١٠ Persian[b] ۴ ۵ ۶ Urdu[c] ۴ (Ր) ۶ (Ч) ۷ (<) Abjad numerals ا ب ج د ه و ز ح ط ي

1. ^ U+0660 through U+0669
2. ^ U+06F0 through U+06F9. The numbers 4, 5, and 6 are different from Eastern Arabic.
3. ^ Same Unicode characters as the Persian, but language is set to Urdu. The numerals 4, 6 and 7 are different from Persian. On some devices, this row may appear identical to Persian.

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.[4] 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 and denominator on the left and right of the fraction slash respectively, e.g. ٢/٧ (27).

The normal comma , or the symbol ٫ is used as the decimal mark, as in ٣,١٤١٥٩٢٦٥٣٥٨ (3.14159265358).

The Arabic comma ، or the symbol ٬ may be used as a thousands separator, e.g. ١،٠٠٠،٠٠٠،٠٠٠ (1,000,000,000).

Contemporary use

Modern-day Arab telephone keypad with two forms of Arabic numerals: Western Arabic numerals on the left and Eastern Arabic numerals on the right

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 now 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. The next nine letters are from the local Dhives Akuru digits (old system with the letter dnaviyani between gaafu and seenu). The next few letters are derived from secondary modifications to some of the previous letters.[5]