103 LearnersLast updated on July 4th, 2025
Ordinal Numbers
We often describe the position of various objects, people, or places using words such as 1st, 2nd, 3rd, and so on. These are known as ordinal numbers. Ordinal numbers are used to represent the rank of people or objects. For example, Annie is ranked 3rd in her school. Let’s now learn about ordinal numbers in detail.
What are the Ordinal Numbers?
Ordinal numbers are used when we want to represent an object’s rank or position in relation to other objects. For instance, 1st is the ordinal form of the number 1.
Suppose you want to list the positions of students in a class based on their test scores:
1st, 2nd, 3rd, etc.
How to Write Ordinal Numbers?
To write ordinal numbers, we add suffixes to the cardinal number base. The most commonly used suffixes are -st, -nd, -rd, or th, based on the number.
It often follows the form: Ordinal Number = Cardinal Number + Suffix
For example, 2 + nd = 2nd.
- We use “-st” for numbers ending in 1 like 1st, 21st and 31st. However, this does not apply to numbers ending in 11 (e.g., 11th, 111th).
- Use ‘-nd’ for numbers ending in 2, except numbers like 12, 112, 212, etc. (e.g., 2nd, 22nd, but 12th).
- Use ‘-rd’ for numbers ending in 3 (e.g., 3rd, 23rd, 33rd)
- Use ‘-th’ for all other numbers (e.g., 4th, 5th, 6th, 11th, 12th, 13th)
What is Ordinality?
The term ordinality refers to the position or rank of an object in a sequence. Ordinality determines the order in which something is placed in a list or sequence. For example, the order of numbers in the set {1, 2, 3, 4} is described as first, second, third, and fourth.
This should not be confused with cardinality, which refers to the size or quantity of objects in a sequence.
List of Ordinal Numbers from 1 to 100:
Learning about ordinal numbers from 1 to 100 can help you understand the position of different elements in a sequence. Ordinal numbers generally follow a predictable suffix pattern, especially from 1 to 20. Here’s a list of ordinal numbers from 1 to 100 :
Difference Between Ordinal, Cardinal Numbers, and Nominal Numbers
Ordinal, cardinal, and nominal numbers are different numerical representations of the position, quantity, or classification of different objects. Understanding their differences will help you familiarize yourself with the concepts:
|
Cardinal Numbers |
Ordinal Numbers |
Nominal Numbers |
|
Indicates the number of objects. |
Indicates the exact position or rank. |
Indicates classifications or labels. For example, jersey numbers in sports |
|
For example, 1, 2, 3, and so on. |
Example: 1st, 2nd, 3rd, etc. |
For example, Ronaldo wears Jersey number 7. |
|
Addition, subtraction, and other mathematical operations can be used. |
Only a limited set can be used, such as for rankings |
There are no significant mathematical operations. |
|
Can be applied to count the number of objects. |
Indicate rank positions in a sequence. |
Specifically used for naming or identifying objects. |
Real-Life Applications of Ordinal Numbers
Ordinal numbers are largely utilized in representing the position, rank, or order of things. Let’s now go through a few real-life applications of ordinal numbers:
- Ordinal numbers are used to indicate the exact positions of winners in a competition. For example, 1st place, 2nd place, and 3rd place.
- We use ordinal numbers to denote dates.
For example, new year’s eve is celebrated on December 31st.
- The precise location, such as mentioning the specific floor where someone is, can be expressed using ordinal numbers.
For example, Ann is on the 4th floor.
- Ordinal numbers show which chapter a reader is on.
For example, the teacher is in the 6th chapter.
- We use ordinal numbers in specifying precise locations.
For example, we use ordinal numbers in addresses, such as: ‘Ben lives on 2nd Avenue.
Common Mistakes and How to Avoid Them in Ordinal Numbers
Students often make mistakes when trying to position, rank, or label objects. Here are a few common mistakes and ways to avoid them:
Mistake 1
Incorrect Application of Suffix
Some students add incorrect suffixes to the cardinal number.
For example, 31th (incorrect), 31st (correct)
Note that numbers ending in 1, 2, and 3 always take suffixes -st, -nd, and -rd accordingly.
Mistake 2
Spelling Errors in Ordinal Numbers
They may misspell when writing the ordinal numbers.
For example, fortieth, twelveth, nineth (incorrect)
Spot your spelling errors and learn the correct spellings of such numbers.
For example, fortieth, twelfth, ninth.
Mistake 3
Incorrect Shortened Format
In some cases, students write the wrong ordinal numbers like 1nd, 2st and 3th.
Ensure that you write the correct suffixes like 1st, 2nd and 3rd, to avoid inaccuracy.
Mistake 4
Confusion between Ordinal Numbers and Cardinal Numbers
Students confuse the terms cardinal and ordinal.
Remember, the cardinal numbers are used to represent the count of something, whereas, ordinal numbers represent the position of an element. For example, 1st, 2nd, and 3rd.
Mistake 5
Overlooking the Exceptions
Students often forget the special cases in the ordinal numbers.
For example, 11th, 12nd, and 13rd (incorrect), 12th, 13th (correct).
Use -st, -nd, -rd respectively for the numbers that end with 1, 2, and 3 but not for numbers that end with 11, 12, and 13.
Solved Examples of Ordinal Numbers
Problem 1
In a 200-meter race, Sam finished after three other runners. What is Sam’s position?
4th place.
Explanation
Since Sam finished after three other runners, we can conclude that he is in 4th place.
Problem 2
Juan turns 12 years old this week. How should he write it in ordinal form?
12th birthday.
Explanation
The ordinal form of 12 is 12th. So, we write, Juan is celebrating his 12th birthday this week.
Problem 3
Leona lives five floors above the first floor. Write the ordinal form for her floor.
6th floor.
Explanation
Since the first floor is the ground floor, we conclude that Leona is on the 6th floor.
Problem 4
Aldo holds the rank of number 2 in his school. How should we express this in ordinal form?
2nd rank
Explanation
We write the number 2 in ordinal form as 2nd, so we say: Aldo holds the 2nd rank in his school.
Problem 5
Ben, Jake, Peter, and Rio are the top four students in the class respectively. How should we express their positions in ordinal form?
Ben secured 1st place, Jake secured 2nd place, Peter secured 3rd place, and Rio secured 4th place. These are their positions in ordinal form.
Explanation
The top four cardinal numbers are 1, 2, 3, and 4. So to express them in ordinal form, we add suffixes based on the number’s ending digit.
FAQs on Ordinal Numbers
1.What do you mean by ordinal numbers?
2.What is the ordinal number for students ranked 15?
3.Give one major difference between ordinal numbers and cardinal numbers.
4.Give one common real-life example of ordinal numbers.
5.How can children in Canada use numbers in everyday life to understand Ordinal Numbers?
6.What are some fun ways kids in Canada can practice Ordinal Numbers with numbers?
7.What role do numbers and Ordinal Numbers play in helping children in Canada develop problem-solving skills?
8.How can families in Canada create number-rich environments to improve Ordinal Numbers skills?
Hiralee Lalitkumar Makwana
About the Author
Hiralee Lalitkumar Makwana has almost two years of teaching experience. She is a number ninja as she loves numbers. Her interest in numbers can be seen in the way she cracks math puzzles and hidden patterns.
Fun Fact
: She loves to read number jokes and games.
