Conocimiento matemático fundamental en el grado de educación primaria: sistema de numeración decimal y valor posicional

We present a study of future teachers’ conceptual knowledge of the decimal numbering system (DNS) and place value (PV). First, we establish the conceptual knowledge of the DNS and place value as Basic Mathematical Knowledge (BMK) to start the study of teaching and learning of addition and subtraction. Next, we introduce part of a research tool that we have designed to assess the conceptual understanding of the DNS and PV based on two dimensions: namely knowledge of general principles, and knowledge of principles underlying the procedures. When applying the assessment tool to 135 students in a university degree on Primary Education we observe that most of them show a fragmented, incomplete and mechanical understanding of the DNS and PV.