In this book, Francisco Cordero offers a reflective synthesis of his work in educational mathematics for just over three decades. It discusses widely and points out evolutionary moments of the educational problems of mathematics when teachers are asked to relate school mathematics and reality in study plans and programs. What is the reality of the student body? What is the teacher's frame of reference? to achieve the link? To address these questions, Cordero proposes a frame of reference that is the expression of functional knowledge: the uses and meanings of people's mathematical knowledge at work, in the profession - in different academic areas, including mathematics - and in everyday life. his life.