Use surveys and quizzes as a kind of feedback system. Create surveys and polls to get an overview of the level of understanding.
- Crowdsignal: create surveys and polls – https://crowdsignal.com
- Socrative: simple quizzes can be created. There are three types of answers: multiple choice, true/false and free text entry. The participants also see both the question and the answer options on their screen – www.socrative.com