Stop at any point during instruction and ask students to gauge their understanding of the concept. Ask them to indicate how much they understand on a scale of one to five using the fingers on one hand. Five fingers indicates full understanding and one finger shows there is frustration or confusion. Quickly scan the classroom and pinpoint whether a full class re-teach is necessary or perhaps some individual or small group intervention would be more efficient. Using the five-finger scale is most effective in classrooms where students are self-assured and able to reasonably gauge their understanding.