First off, thank you for considering contributing to Simple Math Interpreter.
You can help out by doing the following things:
Currently Github Discussions are in beta so you can raise issues for the features that you wanted to be impemented in the interpreter. When Github Discussions comes out of beta, you can suggest new features there.
Bugs exist in every system. They can irritate you many times. So, to prevent this from hapenning to others, if you find a bug and cannot fix it, please open a issue.
Thank you for considering to improve the program. You can contribute things other than code like adding documentation, fixing a type, adding samples etc. All contributions are welcome.
If you are adding a new feature, please provide tests for the same.