The Pivotal Role of Knowledge Structure and Instructional Design in the Development of Teachers Teaching Mathematics to Students With Intellectual Disabilities

During the last six years, we were engaged in professional development programme for mathematics teachers of special schools for students with intellectual disabilities (IDs). We were able to observe that mathematics teachers of students with IDs are left in a difficult situation where support in subject specific knowledge is lacking. Although the knowledge of the characteristics learners with special educational needs (SENs) as provided by psychology does help to open the door to successful teaching and learning of these students, how to teach subject content with constraints of students’ disabilities is left open. This paper reports some qualitative data collected from the programme, which sorts out several key challenges in the field of mathematics education for students with IDs and demonstrates how the design science of mathematics education helps teachers to address teaching problems. Based on the data, we claim that: (a) teachers’ ability to figure out milestones and intermediate learning states within a prolonged process of knowledge construction is crucial to teach students with IDs; and (b) using a design science approach to create carefully designed teaching units serves a dual role of providing teachers with teaching ideas as well as facilitating their understanding of mathematical knowledge structure.