Three and four-fifths
One fifth PLUS two fifths = 3 fifths
six and three-fifths
1/5 + 3/5 + 1/5 = 1
14 and 3/5
One third of three fifths is one fifth.
one fifth = 20% three fifths = 60%
One fifth plus one fifth is two fifths (2/5).
2 fifths (One of anything) plus (another one of it) is always (two of the same thing). Fifths follow that general rule.
Assuming that you mean "fifths", the answer is three fifths.