<P> The alphabet then had 28 letters, and so could be used to write the numbers 1 to 10, then 20 to 100, then 200 to 900, then 1000 (see Abjad numerals). In this numerical order, the new letters were put at the end of the alphabet . This produced this order: alif (1), b (2), j (3), d (4), h (5), w (6), z (7), H (8), T (9), y (10), k (20), l (30), m (40), n (50), s (60), ayn (70), f (80), S (90), q (100), r (200), sh (300), t (400), th (500), dh (600), kh (700), D (800), Z (900), gh (1000). </P> <P> The lack of vowel signs in Arabic writing created more ambiguities: for example, in Classical Arabic ktb could be kataba = "he wrote", kutiba = "it was written" or kutub = "books". Later, vowel signs and hamzas were added, beginning some time in the last half of the 6th century, at about the same time as the first invention of Syriac and Hebrew vocalization . Initially, this was done using a system of red dots, said to have been commissioned by an Umayyad governor of Iraq, Hajjaj ibn Yusuf: a dot above = a, a dot below = i, a dot on the line = u, and doubled dots giving tanwin . However, this was cumbersome and easily confusable with the letter - distinguishing dots, so about 100 years later, the modern system was adopted . The system was finalized around 786 by al - Farahidi . </P> <P> Before the historical decree by Hajjaj ibn Yusuf, all administrative texts were recorded by Persian scribes in Middle Persian language using Pahlavi script, but many of the initial orthographic alterations to the Arabic alphabet might have been proposed and implemented by the same scribes . </P> <P> When new signs were added to the Arabic alphabet, they took the alphabetical order value of the letter which they were an alternative for: tā' marbūta (see also below) took the value of ordinary t, and not of h . In the same way, the many diacritics do not have any value: for example, a doubled consonant indicated by shadda does not count as a letter separate from the single one . </P>

Where do the oldest written inscriptions from the qur'an appear