Throughout the unit, I used colored paper (non-white paper) when I copy anything that could be later used in a students’ portfolio. This way, throughout the unit, students know which assessments and tasks can be part of their portfolio. It also makes the portfolio organization much easier because students can literally sort through a pile of work and pull out the possibly portfolio components easily.
The idea behind the portfolio is for students to create their own summative assessment of the unit. The big question to ask them as their work on their portfolio is: How can you show your mastery of the skills and ideas of this unit? Which work represents your best effort and understanding?
Additionally, students are asked to think meta-cognitively about their use of the mathematical practice standards during the unit. I have narrowed the list down from all 8 in the beginning, while students familiarize themselves with these.