

That’s funny because I grew up with math teachers constantly telling us that we shouldn’t trust them.
Normal calculators that don’t have arbitrary precision have all the same problems you get when you use floating point types in a programming language. E.g. 0.1+0.2==0.3 evaluates to false in many languages. Or how adding very small numbers to very large numbers might result in the larger number as is.
If you’ve only used CAS calculators or similar you might not have seen these too since those often do arbitrary precision arithmetics, but the vast majority of calculators is not like that. They might have more precision than a 32 bit float though.
On Mac:
If you want an icon you can double click on your desktop, you can put you command in a file with the extension “.command” and mark it as executable. Double clicking it will run the content as a shell script in Terminal.
If you want something that can be put into the Dock, use the Script Editor application that comes with macOS to create a new AppleScript script. Type
do shell script "<firefox command here>"
then find Export in the menu. Instead of Script, choose export to Application and check Run Only. This will give you an application you can put in the Dock.If you want to use Shortcuts, you can use the Run Shell Script action in Shortcuts too.
Finally, if you want something that opens multiple firefoxes at once, chain multiple firefox invocations together on one line separated by an ampersand. There is an option you have to use (–new-instance I think?) to make Firefox actually start a complete new instance.