This study investigates the effect of note-taking strategies on solving reality-based mathematical tasks, such as highlighting relevant information, writing relevant data, and elaborating on information during the solution process. While prior research has highlighted the general benefits of note-taking for learning, few studies have examined how specific note-taking strategies operate within the context of complex, reality-based mathematics tasks. This study extends existing work by systematically analyzing how different note-taking subprocesses interact with student characteristics and influence solving success. Data of 1064 task solutions from students in grades 7–10 (Mage = 14.85, SDage = 1.26) were collected from three task contexts, each at three levels of language, and coded for subprocesses, namely, relevant and irrelevant notes, calculation paths, and elaboration strategies. The methodology included descriptive statistics, correlation analyses corrected for multiple comparisons and generalized linear mixed models to explore the relationship between note-taking strategies, personal factors (e.g., mathematical and language proficiency), and task performance. Effective note-taking strategies, such as writing and elaborating relevant information, significantly contributed to correct task solutions. Conversely, taking irrelevant notes was negatively associated with performance. The generalized linear mixed models indicated that personal characteristics, including general mathematics and language proficiency, predicted task success, text understanding, and various note-taking types. Effective note-taking enhanced students’ capacity to tackle complex problems. These findings address previous calls to examine in detail the subprocesses of solution strategies and underscore the importance of teaching different note-taking strategies to enhance the solving process in reality-based tasks.