THE SCIENCE OF LETTERS · LESSON 2 OF 5 · 12 MIN
The Abjad
The old order of the Arabic letters and their numbers from 1 to 1000, the eastern and western variants, 786 and 66, and chronograms that hide a year in a line of verse.
Before the Hindu–Arabic digits came into use, the Arabs wrote numbers with letters. The system is called the abjad, or ḥisāb al-jummal, "the reckoning of the sums", after its first four letters — alif, bāʾ, jīm, dāl — which are the A-B-G-D of the old Semitic alphabet shared with Hebrew, Aramaic and Phoenician. It is the Arabic cousin of Hebrew gematria and Greek isopsephy, and it is still used to number lists and outlines.