For the bases 2,3,5 and 10 we have produced the numeral coins that allow to represent all numbers up to 100.
The .stl files (ready for 3D print) and the printing instructions can be downloaded: zip.
An article (joint work with Olha Nesterenko) on the numeral coins: link.
CONTACT: antonella.perucca@uni.lu
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International license CC BY-NC-SA 4.0.
The stl files (produced by Dominique Breton) and the app (produced by Imaginary gGmbH) are a courtesy of the University of Luxembourg.
Many thanks to Fabio Génin for useful comments on the first version of the app.