The document discusses the history of negative numbers. It details that negative numbers first appeared in Chinese mathematics texts from the 9th century AD to denote debts. The Indian mathematician Brahmagupta further developed the rules and operations of negative numbers in the 7th century AD. While negative numbers were used in some contexts to represent debts as early as the 9th century AD, they were still controversial and sometimes ignored until the 15th-18th centuries as their meaning and use was established more concretely over time.