摘要：This research aimed to describe the levels of feeling of rightness (FOR) ofstudents. This research used a qualitative method with an explorative type. Thesubjects of this research were 3 students of 5th grade selected from 77 otherstudents in Indonesia. In uncovering FOR subject of this research, instrumentswere used in the form of problems about the open-ended polygon perimeter andinterview guidelines. The data of this research were the subjects' answers to theproblems of polygon perimeter and the results of interviews with subjects relatedto these answers. The data were analyzed using the FOR subject level indicatorrubric. There were three levels of FOR which were the findings in this research,namely low, medium, and high. Low FOR level was indicated by the answerscrossed out and the objectives or goal changed. Medium FOR level was indicatedby crossed out answers, objectives or goals changed, problems text readrepeatedly, indecisive statements about the truth of the answers that have beengenerated, and doubts in determining the steps to be taken. High FOR level wasindicated by answers that were not crossed and goals that were not changed.
