Differences in actual classroom behaviors in teaching with technology between novice and expert teachers were studied for six middle-school mathematics teachers from a large urban/suburban school district in a major metropolitan area. Teachers received inservice training in the use of calculators, and their students were issued calculators for the school year. Teachers were categorized as experts or novices based on their educational background and observations by a superior. Observations and interviews made the differences between experts and novices apparent. Experts were more than twice as likely as were novices to focus on content and process, to determine the difficulty of the task, restructure the task as necessary, redirect student thinking, and check individual work. Experts praised student behavior more and corrected student performance twice as much, while novices were more apt to correct student behavior and were more often seen at their own desks. Novice teachers initiated use of calculators less often than did experts and were less likely to use them in class and less likely to emphasize the importance of estimation in determining the reasonableness of a calculator answer. Implications for other areas of educational technology are discussed. Three tables present study data. (Contains 11 references.) (SLD)