Pre-assessments at the start of teaching new content yielded information on what her students knew and might need, this math teacher found, but led many students to get nervous at a unit's beginning. To gauge students' understandings about math in a more inviting, stress-free way, she simply gave them drawings of protractors and asked "What do you notice? What do you think that might mean?"--then let them experiment with using the devices. She was able to learn much about their understandings while creating a climate of exploration, collaboration, and assessment for learning in math class.