The primary purpose of the research conducted in this dissertation was to explore how students' affective mathematics engagement was revealed in mathematical learning situations. All three studies included in this dissertation used quantitative data to investigate whether the students' affective mathematics engagement was affected by diverse factors (gender, language, immigration status, school characteristics, country or culture, motivation, and implementation of STEM PBL). The research discussed in the first article employed the Trends in International Mathematics and Science Study (TIMSS) 2015 dataset to explore whether the students' affective mathematics engagement was influenced by demographic factors related to the students and the schools. The second article compared a sample of Korean students to a sample of U.S. students in order to understand how culture affects and complicates the understanding of intrinsic and extrinsic motivators, and how this impacted the students' affective mathematics engagement. The research conducted for the third article compared two conditions (STEM PLB instruction and non-STEM PBL instruction) in order to examine how the students' affective mathematics engagement were affected by changes based on participation in STEM PBL instruction, in comparison to those who were taught using traditional mathematical instruction. The results of the first article revealed that students who were male, mainly spoke English at home, or were born in the U.S. had more positive affective mathematics engagement, in comparison to their peers who were female, did not use English at home, or were not born in the U.S. Moreover, students in economically advantaged schools had more positive affective mathematics engagement than students in economically disadvantaged schools. The second article revealed that affective mathematics engagement variables (attitude, emotion, self-acknowledgement, and value) were directly related to motivation variables (intrinsic and extrinsic motivation). Furthermore, this model was supported by the empirical comparison between Korea and the U.S. The third article revealed that students in STEM PBL instruction experienced greater positive affective mathematics engagement in comparison to students in non-STEM PBL instruction. Overall, the results of this dissertation indicate that the affective mathematics engagement of students is impacted by diverse factors, such as gender, language, immigration status, school characteristics, country or culture, motivation, and implementation of STEM PBL. The findings of this dissertation contribute to a better understanding of the factors that can positively impact the affective mathematics engagement of students.
