Resumen de Single unit counting – An impediment for arithmetic learning
Ulla Runesson, Camilla Björklund, Angelika Kullberg
In this paper we direct attention to the single unit counting strategy that is observed to be limiting students’ opportunities to develop their arithmetic skills. We describe what impediments single unit counting may entail when encountering novel subtraction tasks, and how these impediments can be explained. From a sample of 121 interviews of students aged 7-8 we have chosen nine who were using single unit counting as their dominating arithmetic strategy. An analysis based on variation theory reveals that the impediments are related to the students not experiencing numbers as composed units and thereby lack in discerning number relations necessary to handle multi-digit subtraction. Educational implications are discussed grounded in the theoretically driven findings.
