What Is an Ordinal Number: What You Need To Know

Learning mathematical skills can be challenging, and one of the key concepts is the ordinal number. What is an ordinal number? 

Numbers can be divided into several categories, and it is essential to understand which types of numbers are used in certain situations. One of the essential categories of numbers is called the ordinal number. An ordinal number is a number we use to keep track of items in a series. A few common examples include first, second, and third. Even though ordinal numbers can be paired with cardinal numbers, there are several significant differences to keep in mind. Learn more about ordinal numbers and cardinal numbers below.

Defining Ordinal Numbers

The definition of ordinal numbers is that these are numbers used to communicate the position of a specific object in a series. For example, if you hold up the number “2,” someone will probably be able to tell you the number “two.”

On the other hand, it can be difficult for that person to grasp that “two” is different from “second” if you are talking about a number in a series. Even though these are all natural numbers, the topic can still be complex for someone to grasp. While ordinal numbers are countable, it can still be challenging for someone to learn how to use them properly. That is why it is helpful to look at a few examples of ordinal numbers.

Analyzing a List of Ordinal Numbers

If you are learning ordinal numbers or trying to teach them to someone else, it is helpful to start with basic examples. For example, you may want to start with the first ten ordinal numbers. They include:

  • 1st 
  • 2nd 
  • 3rd 
  • 4th 
  • 5th 
  • 6th 
  • 7th 
  • 8th 
  • 9th 
  • 10th 

Remember that pairing these numbers with their written terms is also helpful. They include:

  • First
  • Second 
  • Third 
  • Fourth 
  • Fifth 
  • Sixth 
  • Seventh 
  • Eighth 
  • Ninth 
  • Tenth

It can also be helpful to ask learners to try to craft ordinal numbers for more significant numbers as well. For example, numbers such as twenty-second, thirty-second, thirty-fourth, thirtieth, fortieth, fiftieth, sixtieth, hundredth, and thousandth can be challenging for people to grasp.

It might be helpful to ask students to take these numbers and pair the written number with the numerical counterpart. For example, if you show the number 37th, ask the other person to write “thirty-seventh.” The words can look a bit strange at first, but with a bit of practice, it will be easier for students to grasp that these numbers refer to the position of an object in a series. 

Comparing Ordinal Numbers To Cardinal Numbers

Comparing ordinal numbers to cardinal numbers
In general, we use cardinal numbers to count things

They can also be helpful for students to learn about ordinal numbers as they are compared to cardinal numbers. The definition of a cardinal number is that this is a number that tells us how many there are of something. In general, we use cardinal numbers to count things. When students and children first learn their numbers, they burn them as cardinal numbers. They count cardinal numbers when students learn to count one, two, three, four, and five. However, grasping the difference between ordinal and cardinal numbers can sometimes be challenging. 

If you are talking about a test you have recently taken, you may say something such as, “the second question was straightforward, but the fifth question was very hard.” This is a helpful example of how ordinal numbers might be used, but someone else might say, “the number five question was very hard.” This is an inappropriate use of cardinal numbers.

Even though it is relatively easy to interpret what someone is talking about, it showcases how challenging it can be to figure out whether you should use ordinal or cardinal numbers. The best way to figure out how to deal with this issue is to practice them. They are different types of numbers, and it is essential to figure out which number should be used in which situation. 

Examples of When To Use Cardinal Numbers Vs.Ordinal Numbers

It is important to remember that ordinal numbers always have a suffix on the end of them. So, for example, 2nd, 1st, 3rd, and 10th all have suffixes when you write out their written counterparts. We generally use ordinal numbers for dates and order particular objects. A few examples of using ordinal numbers include:

  • If the date is July 22nd, 2022, you will use ordinal numbers when you write this out. For example, you would write it as July twenty-second, two-thousand, and twenty-two. You would not use cardinal numbers in this situation.
  • If you give a list of people, you will use ordinal numbers. For example, if you were to give the first three presidents of the United States as George Washington, John Adams, and Thomas Jefferson, someone might ask you, who is the third president of the United States? You would say that Thomas Jefferson was the third president of the United States. 
  • As another example, you might be talking about the position of swimmers racing in the pool. For example, if eight swimmers are racing, and Michael Phelps is winning, you could say that Michael Phelps is currently first in the race.

These are a few examples of when you should use ordinal numbers. It is also helpful to consider when you should use cardinal numbers instead. Remember that cardinal numbers are for counting. A few examples of when you might use cardinal numbers include:

  • If someone asks you how many eggs are in a dozen, you may say there are 12 eggs in a dozen. I noticed that there are no suffixes at the end of this. Instead, you would write it out as “there are twelve eggs in a dozen eggs. 
  • If you set the table for dinner, you may ask the host how many people are coming. For example, if the host says they are expecting 6 people, put out 6 settings; you would write this out as “six.”
  • If someone counted the number of people racing in the swimming pool, you might notice that there are eight swimmers. This is another situation where you use cardinal numbers instead of ordinal ones.

If you have questions about when to use which type of number, you should remember that C and O. Cardinal numbers are for “counting,” and ordinal numbers are for “ordering.” The first letter of each word matches when you should use certain types of words. 

Grammar Rules for Using Ordinal Numbers

If you are using ordinal numbers in your writing, keeping a few key roles in mind is important. They include:

  • If you are writing out dates, you do not need to use the ordinal number. However, even though the cardinal number is used when you write out dates, you pronounce it as an ordinal number. For example, if you were to write out the date, “February 10, 2021,” you write it out using cardinal numbers. But, on the other hand, you pronounce it using ordinal numbers.
  • If you are writing out the names of numbered streets, you need to use the ordinal number. Whether you spell out the entire number or leave it as a fundamental numeral, you need to include the ordinal number. For example, you may be giving someone directions in New York City and say that Penn Station is located near 34th Street. Or, you may describe that Times Square is located near Seventh Avenue. Notice that in both of these street names, we used ordinal numbers instead of cardinal ones.
  • If you are using an ordinal number, you do not need to place the ordinal itself as a superscript. So, for example, if you were to say that your 16th birthday party was memorable, notice that you are not using anything as a superscript when writing out the number. 

Some challenges go along with learning ordinal numerals, but these English grammar rules can help you figure out when to use which numbers and terms. You might even want to use a few study materials to help you practice these concepts. That way, you can learn how to incorporate them properly in your writing. You might also want to refer to the style guide for your writing style to see what style you should use in which situation.

Cardinal Numbers vs. Ordinal Numbers in Math

It is also helpful to consider when to use which number in math. First, it is helpful to look at a list of ordinal and cardinal numbers. A brief list includes: 

Cardinal Ordinal

  • 1 One 1st First
  • 2 Two 2nd Second
  • 3 Three 3rd Third
  • 4 Four 4th Fourth
  • 5 Five 5th Fifth
  • 6 Six 6th Sixth
  • 7 Seven 7th Seventh
  • 8 Eight 8th Eighth
  • 9 Nine 9th Ninth
  • 10 Ten 10th Tenth
  • 11 Eleven 11th Eleventh
  • 12 Twelve 12th Twelfth
  • 13 Thirteen, 13th Thirteenth
  • 14 Fourteen 14th Fourteenth
  • 15 Fifteen 15th Fifteenth
  • 16 Sixteen 16th Sixteenth
  • 17 Seventeen 17th Seventeenth
  • 18 Eighteen 18th Eighteenth
  • 19 Nineteen 19th Nineteenth
  • 20 Twenty 20th Twentieth
  • 21 Twenty-one 21st Twenty-first
  • 22 Twenty-two 22nd Twenty-second
  • 23 Twenty three 23rd Twenty-third
  • 24 Twenty-four 24th Twenty-fourth
  • 25 Twenty-five 25th Twenty-fifth

If you need to, you can continue this chart perpetually. Then, in math, you must figure out whether you are dealing with cardinal or ordinal numbers. If you directly involve the number in the calculation, you need to use the cardinal number. An example of this includes:

  • 1 + 2 = 3
  • 1 x 2 = 2
  • 1 – 2 = -1
  • 1 / 2 = 0.5

If you were to speak these calculations out loud, you would use cardinal numbers, not ordinal numbers. On the other hand, if you are trying to explain to someone how to do a specific type of equation, you would use ordinal numbers to describe the steps they would follow. For example:  “In the order of operations, you work the parentheses and exponents first. Then, you do multiplication and division second. Finally, you do addition and subtraction third.” Again, you need to use ordinal numbers because you are giving an order of steps.

FAQs About What is An Ordinal Number

What is an ordinal number in maths?

In math, ordinal numbers are numbers used to describe an object’s position in a series. Some of the most common examples of ordinal numbers include 1st, 2nd, 3rd, 4th, and 5th. In addition, every cardinal number has an ordinal number that is paired with it, and you use ordinal numbers for ordering something. 

What is an ordinal number in words?

We refer to the written word with each number when talking about ordinal numbers and words. For example, the ordinal number words that go with the above numbers are first, second, third, fourth, and fifth. These numbers are used for the same purpose. We are using numbers to describe the position of an object in a series. 

What does ordinally mean?

Ordinal means that it is ordered in a list, and ordinally means in order. There has to be a specific position for the object in the list to be described with an ordinal number. For example, if a set of students is in a line, you may be asked to identify the student at the front of the line. This means you are looking for the first student in line, an ordinal number. 

What is the ordinal number of the letter A?

The alphabet has a total of 26 letters. A is the very first letter in the alphabet. Therefore, the ordinal number of the letter A is first. 

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