1 first
2 second
3 third
4 fourth
5 fifth
6 sixth
7 seventh
8 eighth
9 ninth
10 tenth1l eleventh
11 eleventh
12 twelfth
13 thirteenth
14 fourteenth
15 fifteenth
16 sixteenth
17 seventeenth
18 eighteenth
19 nineteenth
20 twentieth
21 twenty-first