Spelling of Ordinal Numbers
Just add th to the cardinal number:
four  fourth
eleven  eleventh

Exceptions: 
one  first
two  second
three  third
five  fifth 
eight  eighth
nine  ninth
twelve  twelfth 
In compound ordinal numbers, note that only the last figure is written as an ordinal number:
421st = four hundred and twentyfirst
5,111th = five thousand, one hundred and eleventh
Figures
When expressed as figures, the last two letters of the written word are added to the ordinal number:
first = 1st
second = 2nd 
third = 3rd
fourth = 4th 
twentysixth = 26th
hundred and first = 101st 
Titles
In names for kings and queens, ordinal numbers are written in Roman numerals. In spoken English, the definite article is used before the ordinal number:
Charles II  Charles the Second 
Henry VIII  Henry the Eighth 