Ordinal numbers
Spelling of Ordinal Numbers
Just add th to the cardinal number:
four  fourth
eleven  eleventh
Exceptions:
one  first  five  fifth  eight  eighth 
two  second  nine  ninth  
three  third  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  third = 3rd  twentysixth = 26th 
second = 2nd  fourth = 4th  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 
1st first  20th twentieth 
2nd second  21st twentyfirst 
3rd third  22nd twentysecond 
4th fourth  23rd twentythird 
5th fifth  24th twentyfourth 
6th sixth  25th twentyfifth 
7th seventh  26th twentysixth 
8th eighth  27th twentyseventh 
9th ninth  28th twentyeighth 
10th tenth  29th twentyninth 
11th eleventh  30th thirtieth 
12th twelfth  40th fortieth 
13th thirteenth  50th fiftieth 
14th fourteenth  60th sixtieth 
15th fifteenth  70th seventieth 
16th sixteenth  80th eightieth 
17th seventeeth  90th ninetieth 
18th eighteenth  100th one hundredth 
19th nineteenth  