Engage students to assess their comprehension with on the fly quick questions or formal quizzes through Socratic. Check for understanding by blasting out multiple choice, T/F or Short answer questions. Get instant feedback about student knowledge to differentiate lessons for maximum effectiveness. You can have up to 5 quizzes on a free account. Pro accounts for unlimited quizzes are $90 a year. We have plenty of other free quiz alternatives though. I think this tool would be most useful for the quick individual activity questions and exit tickets.