Download the 4-page PDF of the puzzles for free from Google Drive here.
I wanted my pieces to be thick so they'd stay together. In order to do this, I glued the printed puzzles onto thin sheets of craft foam (I recommend FOAMIES glue). I then glued various scrapbooking papers (a different design for each puzzle) on the back. Lastly, I used a exacto craft knife to cut the pieces out once the pieces were totally dried.
Truthfully, it was a pain. While I achieved my objective, if I had it to do all over again, I'd skip the craft foam and just glue the scrapbooking papers to the backs of the puzzles and maybe laminate (for durability). Cutting them out would be MUCH easier.
Play = Practice
I dumped them all number side up in front of my son and let him work through finding each 3-piece puzzle, matching 0.5, 1/2, and 50%, for example. When he thought he had all three pieces of a puzzle found, he turned them over to check that they all had the same paper on the back. Voila! That's the self-checking part.
The papers are necessary because not all the puzzles have different shaped pieces.
My son really loved this challenge!