This mixed-method study employed quantitative and qualitative methods to examine the nature of first-year undergraduate students' experiences learning mathematics with peers through interactions that have an academic focus and how participation in these experiences (in and outside of math classrooms) relate to students' academic success in precalculus and calculus courses and their retention in mathematics- and science-based programs. Quantitative and qualitative results provided evidence that students have different experiences learning mathematics in-class and outside of class by race/ethnicity, gender, and ability (determined by students' first semester math course). Descriptive statistics and correlation analyses revealed that in both of these contexts first semester math course had the strongest relationship to students' level of participation in ACPIs. ANOVAs and multiple comparisons revealed differences in students' participation in in-class ACPIs by race/ethnicity and ability. Regression analyses revealed that the math course in which students enrolled for their first semester and for their second semester was predictive of students' math course grades during each of those semesters. Students' level of participation in ACPIs did not predict their academic achievement in mathematics or their retention in undergraduate math- and science-based programs after one year. Qualitative analyses resulted in the following assertions (1) When students struggle with learning mathematics their primary resource is the course text. (2) Students recognize the benefit of learning mathematics with other students both in- and outside of class, but they do not do it outside of class! and (3) Formally-organized, out-of-class interactions with undergraduates, TAs, faculty, and professors in math- and science-based programs have a strong influence in helping students to connect with others in these programs. Students report that this can influence their persistence in undergraduate math- and science-based programs. Results of this study provided information about students' learning experiences that can be valuable to undergraduate math and math education faculty and university administrators who are interested in improving undergraduate mathematics education.