Nature of mathematics tasks and what teachers do

Tasks play a critical role in the teaching and learning of mathematics, and are a common feature across all areas of mathematics education research. This review begins with a discussion about definitions of tasks and their typification to allow for a more robust framing of knowledge vis-a-vis tasks. As teachers' work with tasks is critical to the work of students, the next four sections are dedicated to research developments in frameworks and principles about task design, and teachers' selection, modification, and enactment of mathematics tasks. There is scope for further research about how and when teachers notice task affordances and engage in classroom discourse using a shared vocabulary for mathematics tasks.