Rules and Examples for Using Ordinal Numbers in English
Learning how to write ordinal numbers correctly is essential for clear English communication. Ordinal numbers help us show order, ranking, and position in sequences, which appear often in school exams, daily writing, and even spoken English. Mastering these will help you avoid common mistakes and score better in competitive exams.
| Type | Form | Example | Usage |
|---|---|---|---|
| Ordinal Number (Word) | first, second, third, fourth, etc. | first prize | She won the first prize. |
| Ordinal Number (Number + Suffix) | 1st, 2nd, 3rd, 4th, etc. | 2nd place | He finished 2nd in the race. |
| Cardinal Number | one, two, three, etc. | three apples | I ate three apples. |
What Are Ordinal Numbers?
Ordinal numbers are words or numbers that show the position or order of things in a list, sequence, or rank. Examples include “first,” “second,” or “3rd.” They help explain the order of events, people, places, and more in English sentences.
Ordinal Numbers vs. Cardinal Numbers
It’s easy to confuse ordinal and cardinal numbers, but they have different purposes. Cardinal numbers count (one, two, three), while ordinal numbers show order (first, second, third).
| Type | Example | Meaning |
|---|---|---|
| Cardinal Numbers | one, two, 3, 15 | The actual quantity |
| Ordinal Numbers | first, second, 3rd, 15th | Position in a sequence |
Ordinal Numbers List (1–20)
Here is a list of ordinal numbers and their correct forms. This helps you check spelling and suffixes quickly during homework or tests.
| Number | Ordinal (Word) | Ordinal (Number + Suffix) |
|---|---|---|
| 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 |
| 13 | thirteenth | 13th |
| 14 | fourteenth | 14th |
| 15 | fifteenth | 15th |
| 16 | sixteenth | 16th |
| 17 | seventeenth | 17th |
| 18 | eighteenth | 18th |
| 19 | nineteenth | 19th |
| 20 | twentieth | 20th |
Rules for Writing Ordinal Numbers Correctly
Follow these steps to use ordinal number suffixes and avoid common spelling errors.
- Numbers ending in 1 use "-st" (1st, 21st), except 11 (11th).
- Numbers ending in 2 use "-nd" (2nd, 32nd), except 12 (12th).
- Numbers ending in 3 use "-rd" (3rd, 23rd), except 13 (13th).
- All other endings use "-th" (4th, 5th, 20th).
- Compound numbers (above 20) are hyphenated: twenty-first (21st).
- Some spellings change: five → fifth, nine → ninth, twelve → twelfth.
Using Ordinal Numbers in Sentences and Dates
Ordinal numbers often appear in dates, rankings, addresses, and instructions. Below are some example sentences and date usages to help you.
| Use | Example |
|---|---|
| Ranking | She finished 2nd in the race. |
| Date (spoken) | My birthday is on the 5th of April. |
| Date (written, formal) | April 5 |
| Instructions | Take the third left at the crossing. |
| Anniversaries/Centenaries | We celebrated our 25th wedding anniversary. |
| Academic Years | She is in her second year at school. |
Common Mistakes and Confusing Ordinals
Students often make mistakes with special suffixes and irregular spelling. Here’s how to avoid them:
- It's 21st, not 21th. Always use -st for numbers ending with 1 except 11.
- Use 3rd for 3, 23rd, but 13th for 13.
- 12 is twelfth (not "twelveth"), and 9 is ninth (not "nineth").
- For dates, use ordinal numbers only when the day comes before the month: "the 4th of July" or "4th July," but write "July 4" without the suffix in formal contexts.
- Hyphenate compound ordinals: twenty-second, thirty-first, etc.
Quick Practice: Fill in the Blanks
Try these practice questions to test your understanding of ordinal numbers:
- May is the _______ month of the year. (5th/fifth)
- She stood _______ in line. (2nd/second)
- My birthday is on the _______ of December. (12th/twelfth)
- He won the _______ prize in the contest. (1st/first)
- Ravi was _______ to solve the puzzle. (3rd/third)
For more on sentence order, try Order of Words in a Sentence. For basic grammar, visit Basics of Grammar.
At Vedantu, we make grammar topics like ordinal numbers simple and easy to memorize. Mastering ordinal numbers supports your exam preparation, daily communication, and advanced writing. Use this page for quick review, and remember to check spelling and suffixes carefully. Strong basics here help you succeed in every area of English.
FAQs on How to Write Ordinal Numbers Correctly
1. How do you write ordinal numbers like 1st, 2nd, 3rd?
Ordinal numbers show position or rank (e.g., first, second, third). The rules for writing them are straightforward: use -st for numbers ending in 1 (except 11), -nd for 2 (except 12), -rd for 3 (except 13), and -th for all others. For example: 1st, 2nd, 3rd, 4th, 5th, 11th, 12th, 13th, 21st, 22nd, etc.
2. What are the main rules for using -st, -nd, -rd and -th?
The suffixes for ordinal numbers follow these rules: add -st to numbers ending in 1 (except 11, which uses -th), -nd to numbers ending in 2 (except 12, which uses -th), -rd to numbers ending in 3 (except 13, which uses -th), and -th to all other numbers. This covers most ordinal numbers in English.
3. What is the difference between ordinal and cardinal numbers?
Cardinal numbers represent quantity (one, two, three), while ordinal numbers indicate position or rank (first, second, third). Cardinal numbers answer 'how many?', whereas ordinal numbers answer 'which one?' or 'what position?'.
4. How are ordinal numbers used in dates and addresses?
Ordinal numbers are frequently used in dates (e.g., October 21st, 1985) and sometimes in addresses (e.g., 1st Street). They specify a sequence or position within a larger context. Note that in formal writing, ordinal numbers in dates are common.
5. Is it correct to write 21st or 21th?
It's 21st. The rule is to use -st for numbers ending in 1 (except 11, 111, etc.), -nd for numbers ending in 2 (except 12, 112, etc.), -rd for numbers ending in 3 (except 13, 113, etc.), and -th for all others. This is a common point of confusion in writing ordinal numbers.
6. Why do ordinal numbers like 11th, 12th, and 13th use “-th” instead of “-st” or “-nd”?
This is an exception to the general rule. The numbers 11, 12, and 13, along with their multiples (21, 31, etc.) and 100, use the -th suffix. These are exceptions, so memorising these is important for accurate English grammar.
7. Should I use a hyphen for larger ordinal numbers (e.g., twenty-first)?
Yes, use a hyphen in compound ordinal numbers like twenty-first, thirty-second, etc. This improves readability and clarity.
8. When should I spell out ordinal numbers versus using numerals with suffixes?
Generally, spell out ordinal numbers when writing formally or at the beginning of a sentence (e.g., First, we...). For more concise writing or in lists/tables, use numerals with suffixes (e.g., 1st, 2nd).
9. How do ordinals work in formal academic or scientific writing?
In formal writing, ordinal numbers are generally spelled out (first, second, etc.) or written with suffixes (1st, 2nd, etc.). Consistency is key; choose one style and stick to it throughout your document for a professional look.
10. Can ordinal numbers be used as nouns and adjectives in sentences?
Yes, ordinal numbers can function as both adjectives (describing nouns) and nouns. For example, in 'She finished first,' 'first' is an adjective describing 'she.' In 'He won first place,' 'first' is a noun indicating position. Using them correctly is vital for fluent English.
11. How do you write ordinal numbers in English?
To write ordinal numbers in English, you need to understand their suffixes: -st for numbers ending in 1 (except 11), -nd for 2 (except 12), -rd for 3 (except 13), and -th for all others. For instance, 1st, 2nd, 3rd, 4th, 21st, 22nd, 100th. This knowledge is crucial for accurate English grammar and exam success.
12. Which is the correct form of the ordinal number?
The correct form depends on the number. For numbers ending in 1 (excluding 11 and multiples of 11), use -st (e.g., 1st, 21st). For numbers ending in 2 (excluding 12 and multiples of 12), use -nd (e.g., 2nd, 22nd). For numbers ending in 3 (excluding 13 and multiples of 13), use -rd (e.g., 3rd, 23rd). For all other numbers, use -th (e.g., 4th, 11th, 100th).
13. How to write 1st, 2nd, etc.?
1st (first), 2nd (second), and 3rd (third) are the ordinal numbers for 1, 2, and 3 respectively. The patterns continue, with -th used for most others: 4th (fourth), 5th (fifth), etc. Mastering these basic ordinal numbers is essential for correct writing and reading.
14. Is it 21st or 22th?
It is 21st. Remember the rule: -st for numbers ending in 1 (except 11 and its multiples), -nd for numbers ending in 2 (except 12 and its multiples), -rd for numbers ending in 3 (except 13 and its multiples), and -th for all others. This is frequently tested on English exams.
