Four hours is not a "fraction of the day"... Fraction, in colloquial speech refers to a unit that is so small as to be insignificant. Four hours out of 16 waking hours is 25% of the day. That's not a proper use of the term fraction, teenager. If it is, perhaps you won't mind eating 25% less, or having 25% less bed to sleep on, or perhaps 25% less computer power to play this game on, 25% less video game budget from your parents or 25% less pay from your burger flipping job.
See what I mean, teenager?
Umm excuse me there but anything less than a whole of something is a fraction of it.
put in simple terms
anything less than 24 hrs is a fraction of a day
23 hours yes is almost the whole day but can still be considered a fraction of the day