The purpose of this qualitative case study was to explore how nontraditional community college students experienced, understood, and applied mathematical reasoning skills while engaged in active-learning pedagogy in an introductory biology course in a Southwestern United States Community College. The underlying theory was the Wigfield and Ecles Expectancy Value Theory (EVT) and Active Learning models of Savin-Baden and Hmelo-Silver guided the research. Data was gathered from freshman biology students in a community college via questionnaires, interviews, a student-based focus group, and an instructor-based focus group. Demographic data from the questionnaires allowed the selection of six students for interviews; four others participated in a focus group. Three instructors participated in a focus group to provide information about their classroom practices and student skills. The most significant result of the data analysis in this qualitative case study was that though the respondent nontraditional student were unprepared for math content in Biology classes they felt no significant math anxiety and did not dislike math. The students entered their classes confident of their abilities. Nontraditional students' experience and understanding of the mathematical concepts presented to them in the biology classes were greatly influenced by their own personal background, which aligned with EVT principles. Instructor pedagogy and active learning positively influenced student navigation of the math coursework in their Biology classes. [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.]