Answer:
All ordinal numbers carry a suffix: -nd, -rd, -st, or -th. Ordinal numbers can be written out as words (second, third) or as numerals followed by abbreviations (2nd, 3rd).
1: first, 1st
2: second, 2nd
3: third, 3rd
4: fourth, 4th
5: fifth, 5th
6: sixth, 6th
7: seventh, 7th
8: eighth, 8th
9: ninth, 9th
10: tenth, 10th
11: eleventh, 11th
12: twelfth, 12th
20: twentieth, 20th
21: twenty-first, 21st
22: twenty-second, 22nd
23: twenty-third, 23rd
24: twenty-fourth, 24th
30: thirtieth, 30th
100: one hundredth, 100th
1000: one thousandth, 1,000th
1 million: one millionth, 1,000,000th
