Yes! I like the original idea of HTML, where the client chooses the styling not the website. That way the web cloud be completely consistent, just pure information.
You can get the same effect if you model the expression as a free algebra (ADT). You can then simplify the terms in the same way.
The paper: "The design of a pretty printing library", by Hughes, explains this nicely.
The main difference is that algebras are more natural in FP and coalgebras in OOP, but they can mostly do the same things, just a bit differently. Actually you can also do algebras in OOP as well (visitor pattern) and coalgebras is FP.
Basically my point was that you should use the simplest abstraction that gets the job done. Even if you implemented max and pow as objects, for your specific use case, you would probably just call the pure functions inside.
Why not make max or pow an object then? If you can model something as a pure function, then it should be a function. You can always add memorization later, if needed. OOP is fundamentally different from FP, objects are not just higher order functions, they are also coalgebras. There is no need to force every peg into a coalgebra hole.
If the app you are using to scan the QR code doesn't ask you for permission before opening the web page that's the problem with the app not the QR code...