SMP Interact is a major new mathematics course for Key Stages 3 and 4. The Key Stage 3 books have been written to support the new Framework for teaching mathematics: Years 7, 8 and 9, both in its specific content and in its general interactive approach to teaching. All the materials have been fully trialled in the classroom, and working teachers from a wide variety of schools have been involved at all stages of writing, trialling, and improving. Teacher's Guide to Book C2 accompanies the second book of the C (Circle) series, which provides a route to the Key Stage 3 SATs at levels 5-7. It contains suggestions for teacher-led activities, including whole class discussion, and guidance on the pupil's materials.