He's in first place. He's in first place.
=====Definition=====
Ordinal numbers indicate order, sequence or position.
| 1st | first | 20th | twentieth |
| 2nd | second | 21st | twenty-first |
| 3rd | third | 22nd | twenty-second |
| 4th | fourth | 23rd | twenty-third |
| 5th | fifth | 24th | twenty-fourth |
| 6th | sixth | 25th | twenty-fifth |
| 7th | seventh | 26th | twenty-sixth |
| 8th | eighth | 27th | twenty-seventh |
| 9th | ninth | 28th | twenty-eighth |
| 10th | tenth | 29th | twenty-ninth |
| 11th | eleventh | 30th | thirtieth |
| 12th | twelfth |
|
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| 13th | thirteenth | 40th | fortieth |
| 14th | fourteenth | 50th | fiftieth |
| 15th | fifteenth | 60th | sixtieth |
| 16th | sixteenth | 70th | seventieth |
| 17th | seventeenth | 80th | eightieth |
| 18th | eighteenth | 90th | ninetieth |
| 19th | nineteenth | 100th | (one) hundredth |
Note that we usually write smaller numbers in words (tenth) and bigger numbers in figures (40th), although there is no strict rule for this.
There are a lot of uses, for example, to talk about dates and anniversaries and to give directions.
=====Examples=====
It's his 35th birthday.
And in the second half of last year...
Your room is on the fourth floor.
Hello, nice to meet you. Is this your first visit to the UK?
He's nervous because it is their first date.
They're celebrating their 50th anniversary.