Also, an LLM is massively overpowered for doing a calculation compared to using a calculator (as well as often being less accurate)!

Usually, if you want a calculation done, you don't know how to do it on a calculator, and you need an LLM to tell you how to do it, you'll get better resullts if you ask the LLM to write you a Python program to do the calculation, and then you run the program, than if you have the LLM attempt to do the calculation in its head. Mental arithmetic is not their forte.