Ordinal numbers of 1 and 20: 20th.

Ordinal numbers of 2 o'clock and 30 o'clock: 30th

Ordinal numbers of 3 and 40: 40th.

Ordinal numbers of 4 and 50: 50th.

Ordinal numbers of 5 and 60: 60th

Ordinal numbers of 6 and 70: seventieth

Ordinal number in 7 and 80: eightieth

Ordinal number in 8 and 90: ninetieth

Extended data

Ordinal number is a kind of numeral, which is mainly mentioned in English grammar and expressed as "which number" in Chinese. In addition, when describing your date of birth, you will also use ordinal numbers in your birthday. For example: May 1 day (May 5 1).

Sometimes ordinal numbers can be expressed by abbreviations. The main abbreviations are as follows:

1, the first one-1st

2. Second-second

3. Third-third

4. Fourth-fourth

5, sixth-sixth

6, 20th-20th.

7. 23rd-23rd

Where 1st, 2 and 3 are special forms, and the rest are Arabic numerals followed by th.