Children enter kindergarten with variable levels of mathematics skill and knowledge gained from informal learning opportunities at home, preschool, and daycare. Many perform well once they receive formal mathematics instruction. However, if students do not develop an initial understanding of the most basic aspects of formal mathematics, they are likely to have difficulty understanding or succeeding at mathematics they will encounter in first grade and beyond. The primary research for this study was how successful was the classroom implementation of the KinderTEK mathematics intervention during the project's Feasibility Testing phase. The KinderTEK feasibility study was conducted winter/spring of 2013 in a moderate sized school district in the Pacific Northwest. KinderTEK was implemented in 10 classes; a mix of morning and afternoon classes taught by six teachers, two at each school. Teacher and student satisfaction with the KinderTEK student app drawn from interviews and survey response data indicated that the majority of students and teachers were satisfied with KinderTEK. The conclusions reported studies that seek to determine the overall impact and effectiveness of an individualized, technologically delivered kindergarten mathematics intervention face significant challenges. However, in spite of the challenges, the results are important to the iterative process of curriculum development. Lessons learned throughout usability trials and the feasibility study reported became valuable tools for the continued adaptation and refinement of the KinderTEK intervention in preparation for larger scale pilot study investigations. Tables are appended.