"Ticket to leave" (or "exit ticket") is an ideal way to end a class.
It can serve a number of purposes: provide feedback to the teacher about the class; require the student to do some synthesis of the day’s content; challenge the student with a question requiring some application of what was learned in the lesson.
The prompt or question should require only a brief time to respond to, certainly no more than five minutes, but perhaps only 1-2 minutes. The “ticket to leave’ is not intended as a major task, rather, a quick summarizer having one of the purposes listed above. The responses should not be part of formal assessment, but it can provide valuable feedback to the teacher.
Some possible prompts or questions to use for the "ticket to leave":
Usually, “tickets to leave” are handed to the teacher as the students leave. However, you might want to have some or all, in small classes, the students quickly share their responses.
Content by Larry Wakeford, Brown University. Source: https://www.brown.edu/sheridan/teaching-learning-resources/teaching-resources/course-design/classroom-assessment/entrance-and-exit/sample