assuming you're just talking about fluid, there are 2 and 1/3 fifths in a half gallon. a fifth is 750 ml, where a half gallon in 1.75L or, 1750ml, in regard to spirits. This isn't a true half gallon though, it's actually about 5 fluid ounces short, but American metrics say close enough.
A fifth is 1/5 of a gallon. Therefore, 2.5 fifths would be half a gallon.
7.5
There are 2.5 of them.
One half gallon is enough to fill one half gallon.
No, one half is 50% and three fifths is 60%. One half also equals three sixths and not three fifths.
Three fifths is bigger than one half. Two fifths is smaller than one half.
Two x half gallon cartons is equal to one gallon.
32 half pints makes one gallon
One half is bigger than two fifths because two fifths just before 2.5 fifths which is half.
1/2 US gallon is 1,893cc
1/5 US gallon is 3.2 cups @16 cups per US gallon.