Interest rates, inflation, capitalization, discounts, compound interest, purchasing power, the constant amortization system (SAC), consumption and income are all topics that people come into constant contact with. However, there is some difficulty in understanding the subject and financial calculations. With this in mind, the aim of this paper is to address the process of learning financial mathematics in elementary school, in other words, to show how some financial mathematics topics have been approached in elementary school. To do this, we will analyze the didactic material offered by the Rio de Janeiro state school system. The research will be based on textbooks from the National Textbook Program (PNLD), the oldest of the programs aimed at distributing textbooks to students in the Brazilian public school system, according to the National Education Development Fund (FNDE). In this way, we will help to ensure that students, future citizens, make rational decisions based on an education system that uses appropriate material.