The document provides guidance for teachers on setting purposeful tasks and activities that encourage students to think meaningfully about the concepts being taught. It emphasizes that all tasks should directly help students learn and make progress, not just occupy time. Tasks should present an appropriate level of challenge for all students. The main goal of any activity is to get students to think purposefully about the knowledge and skills being taught by linking new content to existing understanding. Too many tasks in a lesson can distract from learning; it is better to focus on a few substantial tasks that challenge students to work hard and feel proud of their accomplishments.