Abjad
Abjad letter-numerals are the letters of the Arabic alphabet given numerical values. They could thus be used in various combinations to represent any number from one to 1999. It is not a place-notational system, for their value does not depend upon their position relative to one another. Therefore the number 652 would be represented by the letters kha’, [= 600], nun [= 50], and ba’ [= 2], no matter in what order the letters were arranged. The name abjad comes from the 1st four letters in the sequence to which values 1, 2, 3, and four were assigned, that is, letters, alif, ba’, jim, and dal. The symbol for zero was derived from Greek astronomical and mathematical manuscripts where a symbol was frequently used as an abbreviation for the Greek word ouden, meaning “nothing”. The letter-numerals for numbers one through 50 were the same throughout the Islamic lands, but there were differences between the Western areas and the Eastern when it came to assigning letters to the remaining values, as can be seen in the following table:
