Portfolio

A portfolio is a collection of all work a student has done in math. The portfolio can show a student’s “best” work, or work that shows improvement over time. It could be presented as a tangible paper portfolio, an e-portfolio, or a slideshow presentation.
Grade: intermediate, but could be simplified for primary.
For, of, as: as learning because students see where they are at, or where they’ve come.
Summative or Formative? Formative because any ‘products’ would have already been marked. This is to see what needs to be learned moving forward.
Strengths:                                                                                    

Students, parents and teachers can keep these summaries of learning over the years to understand the pace of the student’s learning.

This product can be used as communication between parents, students and teachers.

Having students compile the work they take pride in gives them ownership over their learning.

Weaknesses:                                                                                      

Some students ‘show how they know’ in ways that are difficult to collect and archive (verbally, for example).

Students may be proficient in mathematical skill but lacking the skills necessary to save and compile their work.

Missing context may cause the portfolio to lose meaning over time. Explanation of concepts or the ‘learning story’ behind some products may need to be included.
Source:

http://www.ascd.org/publications/books/100046/chapters/Determining-the-Basics-of-Student-Portfolios.aspx

https://www.commonsense.org/education/lesson-plans/eportfolio-for-the-k-8-student

Sample: