How did Brahmagupta describe positive and negative numbers as property and debts?

In his influential work Brahma-sphuta-siddhanta, the ancient Indian mathematician Brahmagupta established foundational rules for arithmetic involving negative and positive numbers. He conceptualized these values through the lens of financial transactions: he referred to positive numbers as "property" and negative numbers as "debts."1

By framing these quantities in this manner, Brahmagupta was able to formalize the rules for operations such as addition, subtraction, multiplication, and division involving negative values, effectively treating them as distinct mathematical entities rather than mere absences of value. This approach was a significant development in the history of Indian mathematics, providing a logical framework that allowed for the systematic manipulation of negative quantities in algebraic equations.12