Portfolio Path Graded Math Sample

Has anyone done the portfolio path and submitted a math sample? I know we can submit something from science, but I feel as though I am strongest in math, so I would rather use work from my AB Calc. My main question is what type of work are they looking for? Does it have to be super complex and loaded with problems or can it be 15 or so questions that don’t take 10 mins per question?

Edit: Also are word problems preferred?