Mental Calculus and Arithmetic Teaching in Schools in Rio de Janeiro at the End of the 19th Century

Abstract Mental calculus has been considered a didactic resource valued in Brazil, especially since 1990, with the publication of documents that reinforced its importance for Mathematics teaching in elementary education. However, suggestions for its use are already present in the curricular recommendations for elementary and secondary education since the 19th century. Incorporated into guidelines for arithmetic, mental calculus appears in the wake of proposals for teaching renewal together with the intuitive method ideas, beginning in the 1870s. In this text, the objective is to investigate how mental calculus was present in the prescriptions for the arithmetic teaching and how it was implemented in the teachers practice in schools in Rio de Janeiro. It is intended to highlight the importance of mental calculus in arithmetic teaching in the late nineteenth century in official documents and how mental calculus was presented in didactic works, programs and teaching materials.