Plickers is a classroom response system that allows teachers to assess students in real-time using only a single teacher device, without needing individual student devices. Students are each given a unique printed response card with letters A, B, C, or D on four sides. Teachers scan the room with their device to record which letter each student selects to answer a question. Results appear immediately on the teacher's device and can be projected for the whole class. This system is affordable, engaging for students, and accessible to all.