Usually the Roman number V. For example Henry V is Henry the 5th.
Fifth Century - 5th Century.
one and one-fifth
10 to the fifth power = 105
After the fourth.
0.2
0.2
One-fifth is 1/5 or 0.2
five and one fifth = 5 1/5
The fifth presidents name was Harry Balsonya
.2
5th1/5
0.2