Herold-Blasius, Raja2025-08-262025-08-262024-11-26http://hdl.handle.net/2003/43887Mathematical problem-solving is a 21st-century skill and is demanded in curricula globally. It is a highly complex competence that needs to be supported in the learning process. A common material to differentiate and support within (mathematics) lessons is aid cards. Yet, it remains unclear how students work with such cards qualitatively. In this qualitative, explorative, and type-building study, so-called strategy keys (eight general strategic cards with heuristics on them) have been developed to investigate how primary school students work with strategy keys when solving mathematical problems without prior training and to what extent this supports or hinders their problem-solving process. 16 primary school students were interviewed and videotaped while working on non-routine mathematical problems. The data were coded as product-oriented regarding success and as process-oriented regarding the types of episodes, observable heuristics, and interactions with the strategy keys. Qualitative analyses illustrate four types of processes in which students work with strategy keys. Type 1 and 2 do not benefit from key interactions, while type 3 and 4 benefit from them by showing new heuristics and/or a change of episodes. Implications for future studies and educators are made.enInvestigations in mathematics learninghttps://creativecommons.org/licenses/by-nc-nd/4.0/Aid cardsHeuristicsPrimary schoolProblem solvingSelf- regulation510ResearchArticle