I would have preferred for the function to be called mod, since it's the modulo operation, which in math is represented with a percentage or "mod". Most programming languages use a percentage because of that, so do a lot of calculators.

Yeah, I agree that Elixir is a fine language for some tasks. I personally find the readability somewhat average, but it's very maintainable (due to how it enables clear program structure), the error handling is great, and the lightweight process system is amazing.