This case study examines the changes that took place in a 5th-grade mathematics classroom in Hong Kong when an American-made technological artifact was introduced. Using classroom observation, videotaping, and daily interviews with the teacher and students, the study documents the changes that occurred in the classroom and the factors shaping those changes. Using the artifact prompted the teacher to make changes by altering the content, the sequence of instruction, and the social arrangements for class participation. In addition, the class engaged in extensive discussions about the social implications of solving complex mathematics problems. Most of these changes, however, were made after the attempts to maintain routine instruction broke down. The study suggests that new technologies that are not compatible with the existing practice may lead to intense and sometimes profound reflections about which aspects of the individuals, their environment, and the new artifact to adapt into a new classroom structure. A significant challenge is how to support participants' role shifting and their subsequent psychological changes when new technology is introduced. [Copyright of Cognition & Instruction is the property of Lawrence Erlbaum Associates. Full article may be available at the publisher's website: http://dx.doi.org/10.1207/S1532690XCI1904_1]