Geo is going on a hike in the mountains on a hot summer day he has 4/5 gallon of water that he split into four bottles what fraction of a gallon is he each bottle

The answer is 1/5
Let's pretend it's 4 instead of 4/5
If Geo has to split 4 gallons into 4 bottles, the answer would be 1 right?
but now, it's 4/5, each bottle would have 1/5 of the gallon of water

Then why is the question on here if you know the answer