In this project we test a theoretical idea about how children in grade 1 learn and develop knowledge about addition and subtraction bridging over ten.

For more than thirty years it has been advocated that counting strategies is the path to learning arithmetic. Recently, it has been argued that students can get stuck in the early learnt counting strategies and reject more advanced ones, such as using part-part-whole relations.

Aim with the project

Our aim is to study how the experience of part-whole relations and the ten-base unit contribute to the development of arithmetic skill and develop methods for teaching it. How can the ability to experience part-part-whole relations of number and the ten-base unit be developed? And how can teaching the ability to experience part- part-whole relations of number and the ability to experience the ten-base unit contribute to students' arithmetic learning?

Through a theoretically driven intervention with four teachers and their classes, we will test a pedagogical program aiming at developing first grade students' ability to experience the structure of numbers, and to operate with number relations and the ten-base unit. Individual interviews with 120 students (incl. intervention and control group) before and after the intervention, and in second grade will be conducted, to analyze children's strategies and learning, using variation theory as a framework and qualitative measures.