Mairead Hourigan and Aisling Leavy describe a range of teaching and learning activities focusing on the identification and classification of 2-dimensional shapes. The activities described are useful in highlighting students' misconceptions regarding non-traditioanl and non-prototypical shapes.

"That was the day I decided I was bad at math." Countless times, preservice and in-service teachers make statements such as this after sharing vivid memories of learning multiplication facts. Timed tests; public competitive games, such as Around the World; and visible displays of who has and has not mastered groups of facts still…

In this paper, we describe our learning progressions approach to early algebra research that involves the coordination of a curricular framework, an instructional sequence, written assessments, and levels of sophistication describing the development of students' thinking. We focus in particular on what we have learning through this approach about…