Sa'īdān was born in 1914 into an Arabic family in Safad (Palestine). He was a student of the Arabic College in Al-Quds (Jerusalem) and at the American University in Beirut, where he took the degree of Bachelor of Science in mathematics in 1934. Beirut had a strong tradition of studies in the history of Arabic mathematics, and young Sa'īdān was attracted to this field.
After having a Bachelor from London University, his investigations on Arabic mathematics later earned him a Ph.D. from Khartoum University in Sudan. As Professor of mathematics, Sa'īdān taught in Arabic colleges and universities in Palestine, Sudan, and Jordan. After his retirement in 1979, he became President of the University of Abu-Dis in Jerusalem.
Sa'īdān was a well known historian in the community of historians of Islamic sciences. His works focused on two fields:
- The edition of original texts in the different fields of mathematics practiced in ancient and medieval times (geometry, algebra and arithmetic); in this sense he edited more than 20 texts (see list below in section 4); and
- The analysis of the original texts with the tools of history of science to reconstruct content and retrace intercultural influences. Thus, his work as a historian of mathematics led him to pay a special interest to the influence exerted on the development of Arabic mathematics by the Indian and Greek traditions. But at the same time, he was aware of the fantastic progress represented by methods of demonstration and mathematical discoveries brought about by Arab and Muslim mathematicians. In this sense, he had an overall view on the Arabic mathematical tradition and tended to cover its two main wings in the Islamic East and West, mainly in his reconstruction of the history of Arabic algebra, from its emergence in the work of Al-Khwarizmi in Baghdad in early 9th century, until its later stage in the works of the mathematicians of the Maghrib, Ibn al-Banna al-Murrakushi (d. 1321) and al-Qalasadi (d. 1406).