They Called Them Indian Numerals
Al-Khwarizmi credited India. Fibonacci credited the Arabs. The register was kept carefully for six hundred years and then dropped by the beneficiaries, once the debt stopped being useful to acknowledge.
The ten symbols you do arithmetic with were invented in India, refined in Baghdad, and adopted by Europe. Every stage of that is documented, and at every stage the people receiving them said where they came from.
Brahmagupta, writing in seventh-century India, set out rules for zero as a number in its own right: what happens when you add it, subtract it, multiply by it. Not a placeholder in a column, which several cultures had, but a quantity you can calculate with.
In the eighth century an Indian astronomical text reached Baghdad. Al-Khwarizmi saw what it contained and wrote a treatise introducing the system to the Arabic-speaking world.
He called the numerals al-arqam al-hindiyya. The Indian numerals.
He was not being generous. He was being accurate, and accuracy about provenance was a professional norm.
The system travelled on: refined by generations of Islamic mathematicians, embedded in the algebra al-Khwarizmi built around it, carried west through al-Andalus and the Mediterranean trading ports.