Exactly, so it’s not a native framerate. Some people say that 24 to 25 is insignifficant, while some claim they can hear the differance.
With audio, the difference between 25 fps and 24 fps is about a semitone (the difference between C and C#). It’s small, but it’s enough that most people will notice it if they’re familiar with whatever they’re listening to.
The difference between 23.976 and 24 is 1000:1001, an almost 41 times smaller difference. It’s so slight that the human brain can not perceive the difference.
If you’re worried about the numbers involved, the second is an arbitrary unit of measurement. Pick other units of time, and PAL will have non-natural number units of time, or NTSC could have natural number units of time.
If you’re worried about editing or something, what specifically are you trying to do? Put an ST movie onto VHS?