• An unscaffolded problem is tackled individually by students Students are given about 20 minutes to tackle the problem without help, and their initial attempts are collected in by the teacher.
• Teachers assess a sample of the work The teacher reviews the sample and identifies the main issues that need addressing in the lesson. We describe the common issues (Figure 3) that arise and suggest questions for the teacher to use to move students’ thinking forward. (In Having Kittens, these included: not developing a suitable representation, working unsystematically, not making assumptions explicit and so on).
• Groups work on the problem The teacher asks students to work together, sharing their initial ideas and attempt to arrive at a joint, group solution, that they can present on a poster. The pre-prepared strategic questions are posed to students that seem to be struggling.
• Students share different approaches Students visit each other’s posters and groups explain their approach. Alternatively a few group solutions may be displayed and discussed. This may help for example, to begin discussions on the assumptions made, and so on.