Den här studien har för avsikt att ta reda på hur olika typer av problemlösningsuppgifter påverkar elevernas förmåga att rimlighetsbedöma sina lösningar och svar. Studien syftar också till att ta reda på hur elever relaterar till verkligheten när de löser olika typer av problemlösningsuppgifter. För att uppnå syftet med studien genomfördes en undersökning i flera elevgrupper i årskurs två (ålder 8 år). Resultatet på undersökningen visar att olika typer av problemlösningsuppgifter påverkar hur eleverna resonerar kring rimlighet. Resultatet från undersökningen visar också att olika typer av uppgifter påverkar hur mycket eleverna reflekterar över verkligheten. Det har även framkommit under studiens gång att det är väldigt viktigt att kunna uppfatta det muntliga resonemanget som eleverna för att kunna bedöma hur eleverna kommer fram till lösningar och svar. Mycket av förmågan att bedöma rimlighet framkommer endast genom muntliga resonemanget och är därför väldigt svårt att se i skrivna svar. / This study aims to find out how different types of problem solving tasks affect students’ ability to plausible evaluate their solutions and answers. The study also intends to find out how students relate to reality when solving different types of problem solving tasks. In order to achieve the purpose of the study, a survey was conducted in several classes with grade two students (age 8). The results of the survey shows that the type of problem solving tasks can partially affect the students’ ability to assess plausibility. The results of the survey also shows that different types of problem solving tasks, affect how much the students reflect to reality. During the study it also became clear that the oral reasoning is crucial to perceive in order to be able to assess how students come to solutions and answers. Much of the ability to assess plausibility emerges through oral reasoning and is therefore very difficult to detect in written answers.

This paper investigates the theoretical meaning of plausibility in mathematics from a teacher’s perspective. The study applies a phenomenographic research approach and uses empirical content analysis. The theory used comes from the writings on plausibility assessment from McIntosh (2008). Furthermore, Karlsson & Kilborn’s (2015) and Kilpatrick, Swafford & Findell’s (2001) writings on mathematical modeling has been applied. The data gathered in this study comes from interviewing 6 teachers. The results show that teachers in the study do not work explicitly but rather work implicitly with assessment in plausibility as a complement to their general teaching of mathematics. The results further show that the teachers have the mathematical knowledge and competence to educate in plausibility but that they lack the theoretical- and didactic knowledge to apply it in their teaching. There is also very little research, if any, in this area which is a concern for the development of teaching plausibility assessment.