In case you are trying the MARS MAP Classroom Challenges for the first time, it is recommended that you read the Brief Guide for teachers and administrators before you get started.
Before the lesson, students work individually on an assessment task that is designed to reveal their current understandings and difficulties. You then review their work, and create questions for students to answer in order to improve their solutions.
After a whole-class introduction, pairs of students work together to justify or refute mathematical statements. They do this using their own examples and counterexamples. Students then explain their reasoning to another group of students.
In a plenary discussion students review the main mathematical concepts of the lesson.
Students return to their original assessment tasks, and try to improve their own responses.