This three-article dissertation examines and expands the data pertaining to in-service middle and high school (i.e., secondary) mathematics teachers' use of technology in their classrooms. The first article reports on the administration and validation for use in the United States, of Handal et al.'s (2012) TPACK-M survey that was validated for use in Australia. The data obtained from secondary mathematics teachers in United States were analyzed and compared to the original version used in Australia. The purpose was to strengthen the validity argument for the instrument's use to measure in-service teachers' technological, pedagogical, and content knowledge (TPACK). The second article administered the survey to a group of 30 regional in-service mathematics teachers. The data were analyzed and a small group of nine participants were strategically selected to participate in an interview aimed to find commonalties between teachers who utilize technology for student learning as well as the barriers to teachers who may be hesitant to use technology for instruction purposes. The information gained from these interviews allowed the researcher to develop a professional development workshop protocol that can have maximum impact on a teacher's TPACK and utilization of technology for teaching and student learning. The third article was the implementation of the professional development workshop with a small group of subject specific in-service mathematics teachers. This article was a case study of three teachers as they addressed and overcame their perceived barriers and beliefs about utilizing technology for student learning, not just using technology to augment their normal teaching style. The narrative of the growth of these teachers' TPACK understanding and implementation will be beneficial to others in the field as all teachers are having to navigate the new normal of virtual learning predicated upon them due to the COVID-19 pandemic.