Like many other imperialists, the Aztecs like to have a good idea of what they had conquered. So they compiled large, detailed surveys of their lands, which they recorded in scrolls that included both counts of every household and little maps of every farm. Two of these documents survive, the Codex Vergara and the Códice de Santa María Asunción. They survive because, after the conquest, Aztec landowners produced them to challenge what they thought were unfair tax assessments by their new Spanish overlords. The Codex Vergara is in the news this week because some mathematicians used the survey, along with archaeological mapping of an area where the ancient field boundaries are still visible, to test the accuracy of Aztec surveying. They found that 85% of the values given in the Codex are within 10% of the values they calculated, better than Spanish surveyors did until the 19th century.
The two things that drove mathematical progress in ancient civilizations were land surveying and astronomy.