Expanding a task on base four to base ten in a collaboration between researchers and teachers

In this paper, we focus on the expansion of a task developed in one educational context in another educational context. The working process was conducted as a collaboration within a research team consisting of researchers and teachers. The aim of this paper is to describe how a task designed for students to work in base four, was collaboratively expanded into a task that deals with both base four and base ten. The overarching idea is the importance of early exposure to the structural aspects of the positional system and to advocate for exploring different bases to enhance learning. The theoretical framework of the project is based on learning activity, inspired by the El’konin and Davydov mathematics curriculum. The paper includes an analysis of the task staged in a Swedish classroom, highlighting collaborative design work, task features, and outcomes. The results indicate challenges and insights in students’ understanding of base ten as one of many possible base numbers.