Thermometer of Understanding
Students have to think about directed numbers, (positive and negative numbers), in relation to their learning within the lesson. This method allows all students and particularly the students who aren't 100%, but are better than the amber they always put, to identify and distinguish between their understanding of topics more accurately.
The activity pairs well with a WWW or EBI type plenary getting students to focus on positives, negatives and their next steps.
It is a ready to use plenary idea, all you need to do is print the template and poster.