I refer to the letter Whimsical interpretation of Islam wrong .

The Arabic numbering system was actually invented by the Indians and brought over to the Arabs. I quote Wikipedia :

"The numerals arose in India between 400 BC and 400 AD. They were transmitted first to West Asia, where they find mention in the 9th century, and eventually to Europe in the 10th century. Since knowledge of the numerals reached Europe through the work of Arab and Persian mathematicians and astronomers, the numerals came to be called 'Arabic numerals'."

In Arabic language itself, the Eastern Arabic numerals are called 'Indian numerals' (arqam hindiyyah) and a different set of symbols are used as numerals.

Hope this will correct any misunderstandings.