This study investigates the role of digital cognitive technologies in supporting students' mathematical thinking while engaging with instructional tasks. Specifically, the study sought to better understand how the use of technology is related to the cognitive demand of tasks. Data were collected in four secondary mathematics classrooms via classroom observations, collection of student work, and post-lesson teacher interviews. Opportunities for high level thinking by students were evaluated using the Mathematical Tasks Framework (Stein, Smith, Henningsen, & Silver, 2009). Technology use was evaluated with respect to whether it served to amplify students' thinking by making students' work more efficient or accurate without changing the nature of the task, or whether it was used to reorganize students' thinking by supporting a shift to something different or beyond what the technology was doing for them (Pea, 1985). Results indicate that the mere inclusion of technology in a task was not related to the cognitive demand during any of the three phases of implementation, as technology was used in both high and low level tasks. However, results suggested an association between the level of cognitive demand of a task and the way that technology was used. In general, when technology was used as an amplifier, it was not related to the thinking requirements of the task, while the use of technology as a reorganizer was central to the thinking requirements of the task. The decline of tasks set up at high level often corresponded to technology being used as an amplifier and reorganizer during set up, but as only an amplifier during implementation. Overall, the role of technology in the decline or maintenance of high level thinking during implementation seems to depend more on teachers' classroom practice than any particular issues related to the use of technology. How prepared students were to engage in high level thinking tasks in general, how teachers anticipated students' needs while using technology to engage with the task, and how teachers responded to student questions and difficulties were influential factors in the maintenance or decline of these tasks