# Al-Uqlidisi

**Abu l-Hasan Ahmad ibn Ibrahim al-Uqlidisi** was a 10th century Arab mathematician.

Al-Uqlidisi means the Eudclidian and indicates his occupation with classical Greek mathematics. But it was also generally used in the Arab world for people who made copies of Euclid's elements for sale.

He is not mentioned in any Arabic or other source, his name is only known from a copy of his book *Kitab al-fusul fi'l-hisab al-hindi* , the only surviving copy of which is in Istanbul (Yeni Cami, MS 802, the copy is from 1157). It is dated 952/53 in Damascus . It is the oldest surviving Arabic arithmetic book.

In the book he propagates the Indian numerals and arithmetic and explains the concept of value (as the oldest surviving Arabic work). It shows that he had experience teaching Indian numbers. Square roots are dealt with and fractions in the decimal and sexagesimal system, it is the oldest known text of the decimal fraction calculation. He mentions that for the calculation they worked with drawings in sand, in which intermediate steps could simply be deleted (sand abacus). However, his efforts are aimed at doing without the abacus altogether, and he advocated replacing it with bills on paper and ink. He also has the test of nine .

He claims to have traveled widely and studied all the books on Indian arithmetic.

## literature

- AS Saidan: Al-Uqlidisi, Abu l-Hasan Ahmad ibn Ibrahim, in Dictionary of Scientific Biography , Volume 13, pp. 544-546
- AS Saidan: The earliest extant arabic arithmetic, Isis, Volume 57, 1966, pp. 475-490
- AS Saidan (translator): The arithmetic of al-Uqlidisi. The story of Hindu-Arabic arithmetic as told in 'Kitab al-fusul fial-hisab al-Hindi' (Damascus, AD 952/3), Dordrecht-Boston, Mass., 1978
- Roshdi Rashed: The development of Arabic mathematics: between arithmetic and algebra, London, 1994
- A. Anbouba: Note on a manuscript of al-Uqlidisi (Arabic), J. Hist. Arabic Sci., Vol. 3, 1979, p. 285

## Web links

- John J. O'Connor, Edmund F. Robertson :
*Al-Uqlidisi.*In:*MacTutor History of Mathematics archive .*

## References and comments

- ↑ Use of Indian arithmetic in the sexagesimal system can also be found in later Arabic works
- ↑ This sand abacus was also mentioned by Abu al-Wafa , Nasir ad-Din at-Tusi and Ibn al-Banna .

personal data | |
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SURNAME | al-Uqlidisi |

ALTERNATIVE NAMES | al-Uqlidisi, Abu l-Hasan Ahmad ibn Ibrahim |

BRIEF DESCRIPTION | Arabic mathematician |

DATE OF BIRTH | 10th century |

DATE OF DEATH | 10th century |