TITLE: Mathematics of Indians in America
QUESTION [6 upvotes]: Someone could inform me some material of the history of the mathematics of the Indians in America, especially in Brazil. I searched the internet, but I do not find a serious material.
Thank you.

REPLY [6 votes]: The relevant search term is ethnomathematics. There are several journals devoted to this topic (for instance, Revista latinoamericana de etnomatemática). Browsing them (if you have access to MathSciNet, the relevant MSC class is 01A70) and looking at their references should help you get started. 
Another place to look for this is in journals of history of mathematics (Revista brasileira de história da matemática, for example). The (open access) Journal of humanistic mathematics had a paper last year on ethnomodelling you may also find interesting:

MR3536482. Rosa, Milton; Orey, Daniel Clark. Humanizing mathematics through ethnomodelling. J. Humanist. Math. 6 (2016), no. 2, 3–22.