When were repeating decimals discovered?

Answer 1

Repeating decimals have been understood since the development of decimal notation, which dates back to ancient civilizations. The concept became more formalized during the Middle Ages, particularly in the 10th century with the work of Islamic mathematicians. By the 16th century, European mathematicians, such as Simon Stevin, contributed to the understanding and notation of repeating decimals. However, the recognition of their properties and systematic study emerged in the context of the broader development of number theory in the 17th century.