The most remarkable of those features is the fact that it is written from right to left following the normal direction of the Arabic script.
Written numerals are arranged with their lowest-value digit to the right, with higher value positions added to the left.
That is identical to the arrangement used by Western texts using Hindu-Arabic numerals even though Arabic script is read from right to left: Indeed, Western texts are written with the ones digit on the right because when the arithmetical manuals were translated from the Arabic, the numerals were treated as figures (like in a Euclidean diagram), and so were not flipped to match the Left-Right order of Latin text.
[1] The symbols "٫" and "٬" may be used as the decimal mark and the thousands separator respectively when writing with Eastern Arabic numerals, e.g. ٣٫١٤١٥٩٢٦٥٣٥٨ 3.14159265358, ١٬٠٠٠٬٠٠٠٬٠٠٠ 1,000,000,000.
[citation needed] Sometimes, symbols used in Arabic mathematical notation differ according to the region: Sometimes, mirrored Latin and Greek symbols are used in Arabic mathematical notation (especially in western Arabic regions): However, in Iran, usually Latin and Greek symbols are used.