Very simple OpenSCAD code for coins with math operations on each face for math games. We use the coins with a deck of cards to get our kid excited about math.

Use supports touching base plate. The models/scad files with "coin" in the name are the coins with the operations carved out, while the other files are just the operations that can be glued in. It's a pretty tight fit, so the operations may need to be sanded down or adjusted a bit.

These things are a great way to use up extra filament.

I did a little write up on this project here: smolderingdiode.com