The introduction of technology resources into mathematics classrooms promises to create opportunities for enhancing students' learning through active engagement with mathematical ideas; however, little consideration has been given to the potential for technology to promote a more collaborative approach to learning. This paper draws on data from a three year longitudinal study of senior secondary school classrooms to examine pedagogical issues in using technology in mathematics teaching-where "technology" includes not only computers and graphics calculators but also projection devices that allow screen output to be viewed by the whole class. The researchers theorize and illustrate four roles for technology in relation to such teaching and learning interactions-master, servant, partner, and extension of self. The research shows how technology can facilitate collaborative inquiry, during both small group interactions and whole class discussions where students use the computer or calculator and screen projection to share and test their mathematical understanding. (Contains 23 references and 2 figures.) (Author/ASK)