It fits exactly, and that's what I said- 0/0 is not a number. You can look it up if you don't believe me (I'll save some time-
https://en.wikipedia.org/wiki/Division_by_zero. It deals with the reverse operation and if there is any number which when multiplied by zero yields that number; there is not.)
Your math does not work. If an engine is running, it must be using fuel (energy) even if not much. If it is not running, there is no energy use and probably no distance traveled. And no "miles per gallon" since there no gallons used. In the end, you can
say that the non-running car gets infinite miles per gallon, you could also say that it gets zero MPG; neither are mathematically correct.
This is how arithmetic works, I didn't make the rules

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For the physics nerds- this is like the concept that you can know exactly where something is or how fast it's moving (if moving at all), but not both. To measure velocity, you need motion and time, and when the object is moving, you cannot know where it is because by the time you observe the position, it has moved.... (poorly expressed but generally correct)