Have you tried using "Learning Models" in your math workshop yet? we are team-teachers from Wisconsin, and we use "learning models" in our math and reading workshops as an alternative form of assessment. We teach in a 1:1 environment via Chrome Books. Learning Models allow our students to have voice and choice in how they demonstrate proficiency in standards.
This learning model was used during our 1st math workshop unit of the year. We lay out possible ideas for your students to try, and it covers 4 CCSS math standards. It also includes a 4 point rubric.
Don't forget to check out our blog for student examples and other samples of "Learning Models." Happy Mathing!