Maths investigations clearly have huge benefits; the example in the book was of a Happy Numbers investigation. The open-ended approach not only allows for differentiated approaches, but also encourages mathematical thinking and the development of process skills.
In planning for an investigative task in the classroom, I clearly need to plan carefully the scope of the task, and also the scaffolding I will provide to learners who are stuck, or are struggling for ideas. For example, I might include a list of approaches that students could take to get started on the task, as well as a ‘hints’ table if they are stuck.
Assessing performance on a task like this clearly requires a more considered approach than simply ticking correct answers and giving feedback. I need to consider what approaches a pupil has taken (which may not be explicit – thus I probably need to award marks for clarity of presentation as well as outcomes) and how they might improve their approach. However, this seems to accord closely with good practice in assessment anyway, so I don’t think it should put me off!