So-called Arabic digits were shaped in North Africa
The ten symbols 0–9 that most of the world writes are often called Arabic numerals, also Western digits or Ghubar numerals. Positional decimal ideas are older; these particular shapes are a relatively recent North African design that Europe later adopted.
Arabic speakers in Spain and North Africa brought the direct ancestors of these digits to Europe in the 10th century, when the forms were common from Libya to Morocco. Further east, from Egypt to Iraq and Arabia, scholars used a different set now called Eastern Arabic numerals. The oldest written examples, from Egypt in 873–874 AD, already show three versions of 2 and two of 3, the first sign of that split. Reckoners worked on a board sprinkled with dust, erasing figures as they went, which is why western Arabic writers called the method ḥisāb al-ghubār, calculation with dust. A popular story that each digit's angles count its value has no historical support.
The earliest Western record of the digits 1 to 9 is the Codex Vigilanus of 976 from Al-Andalus. Gerbert of Aurillac, who had studied in Barcelona and later became Pope Sylvester II, promoted them from the 980s. Uptake was slow. Astronomers adopted them first, as manuscripts from 12th-century Bavaria show, and Reinher of Paderborn used them to work out Easter dates.
Fibonacci changed the pace. Raised partly in the Pisan trading post of Bugia, now Béjaïa in Algeria, where his father was a customs notary, he learned what he called the Indians' nine symbols and championed them in Liber Abaci in 1202. His timing matched Italy's commercial boom, when place value made currency conversions far quicker than Roman numerals allowed. For two centuries the advantage stayed largely Italian, partly because abacus manuals were written in Italian dialects.
Printing spread the digits across 15th-century Europe; English examples include a 1445 date on Heathfield Church in Sussex. By 1800 they had nearly replaced counting boards and Roman figures in bookkeeping, leaving Roman numerals to clocks and years. Peter the Great officially dropped Cyrillic numerals in 1699, and Jesuits carried the European forms to China in the early 17th century. In ASCII, keeping only the lowest four bits of a digit's code yields its value.
Source: Arabic numerals
