Technology integration is a critical and longstanding issue in mathematics education. As access to various technology resources increases, so too has the expectation for teachers to use technology to enhance student engagement and understanding. Despite the potential benefits to integrating technology into teachers' instructional practices, teachers often teach near as opposed to with technology. "Teaching near technology" describes teachers using technology in a manner that does not promote opportunities for students to communicate, reflect, and connect mathematical representations. "Teaching with technology," on the other hand, refers to using technology to promote opportunities for students to communicate and reflect on the mathematics involved, as well as use and connect mathematical representations. Which leads me to the question, "How can teachers be supported to teach" with ("as opposed to" near) "technology?" More specifically, "How can teachers be supported to teach" with "virtual manipulatives and activities?" Virtual manipulatives (VMs) are one technology tool that has gained increased attention by teachers, researchers, and organizations as a tool for potentially increasing student engagement and understanding. Although VMs have been used in classrooms for quite some time, limited resources exist to support teachers' efforts to teach with this technology tool. Therefore, the following study investigated a professional development (PD) opportunity for secondary mathematics teachers aimed promoting teachers use of VMs and activities. A task analysis framework and a set of guiding questions were developed and refined during the PD in an effort to support teachers' efforts to teach "with" virtual manipulatives. Teachers' appropriation of practices related to implementing VMs and activities in their classrooms as well as tensions related to their implementation efforts were also explored. A professional development model, set of guiding questions, and task analysis framework are presented as resources to support teachers' efforts to teach "with" virtual manipulatives. It is posited that these resources could be adapted for future endeavors aimed at supporting pre-service and in-service teachers to teach "with" technology-based instructional tasks. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]