The use of computer technology for teaching and learning of mathematics has severalconsequences and does sometimes give rise to both controversies andmisunderstandings. We address these problems by both a philosophical and ahistorical approach, investigating what it actually is that goes on when newtechnologies enter mathematics as a discipline and mathematics education as asocietal practice. Our analysis suggests a focus on continuities in time and place inthe sense that it is necessary to understand the history of “tool use” in mathematicsand the various ways that scholastic and non-scholastic mathematical practices adoptsuch tools. Furthermore we point to the strong interrelation between mathematics asa body of knowledge, mathematical activity and the technologies used formathematical work. Finally we discuss how different theoretical lenses andepistemological outsets give rise to different guidelines and conclusions regarding theuse of computer technology in mathematics education.