11th- the eleventh
2nd- the second
12th- the twelfth3rd- the third 13th- the thirteenth
4th- the fourth 14th- the fourteenth
5th- the fifth 15th- the fifteenth
6th- the sixth 16th- the sixteenth
7th- the seventh 17th-the seventeenth
8th- the eighth 18th- the eighteenth
9th-the ninth 19th- the nineteenth
10th-the tenth 20th- the twentieth