Ordinal Numbers with Definition and Examples
Counting is one of the first things we learn at school. One, two, three – all of us know how to count up to large numbers, like one hundred! We can count on our fingers, in our heads, and write the numbers down on paper too!
Counting numbers are also called cardinal numbers. They help us answer questions starting with “How many?”. For instance, if someone asks “How many tacos do you want?”, you might reply “Two tacos!” Here, ‘two’ is a cardinal number.
But there’s another way of using numbers called ordinal numbers. It’s useful when you’re trying to tell someone the position of an object. Let’s learn more about them.
What are Ordinal Numbers?
Ordinal numbers don’t tell you how many objects there are in total. But in a large collection of stuff, you can easily pinpoint a single object using them! Imagine there are five apples in a row and you want to eat the middle one. What do you say? Something like, “I want the third apple!” Here, ‘third’ is an ordinal number.
Ordinal numbers are named so because they tell you the order of an object in a series. We use ordinal numbers all the time! If someone wins a race, we say they came first. Here, ‘first’ is an ordinal number.
Examples of Ordinal Numbers
There is an ordinal number for every cardinal number! As the cardinal numbers go one, two, three, four, the ordinal numbers go first, second, third, fourth and so on. Let us look at some of the first few ordinal numbers:
Notice something interesting? Almost all of these ordinal numbers end with the letters ‘th’, except for ‘first’, ‘second’, and ‘third’! In fact, for all numbers over 20 whose last digit isn’t 1, 2 or 3, their ordinal number ends in ‘th’!
For example, the ordinal number for 45 is forty-fifth, and for 99 it’s ninety-ninth. But the ordinal number for 21 is twenty-first, and for 53 it’s fifty-third!
Cardinal Numbers vs Ordinal Numbers
Cardinal numbers tell us about the total amount of objects, like 5 cats or 7 dogs. But they cannot be used to tell the position of a single object. If you were 9 years old, you could simply say your age is nine! But what if you wanted to invite someone to your next birthday?
You could say, “Please come to my birthday, when I turn ten!” But that’s a lot of words! Or you could use ordinal numbers and say, “You’re invited to my tenth birthday!” Easy, isn’t it?
Ordinal numbers are used to describe the ranking or order of an object. You can’t use ordinal numbers in place of cardinal numbers! If someone said they’re the second tallest in their class, we wouldn’t know the total number of students in that class!
We know cardinal numbers can be written as 1, 2, 3 and so forth. We can write ordinal numbers similarly too! Take the ordinal number ‘second’. We start with the related cardinal number: 2. Then, we write the last two letters of ‘second’ after 2: 2nd. And there you go! You can now write first as 1st, third as 3rd, and so on!
List of Ordinal Numbers from 1-100
Let’s learn ordinal and cardinal numbers from 1-100:
|Cardinal Numbers||Ordinal Number|
|One Hundred||100||One Hundredth||100th|
Where do we use Ordinal Numbers?
We use ordinal numbers in our day-to-day lives. In competitions, the top three positions are first, second and third! In an elevator, we press a button to go to the sixth floor! We also use ordinal numbers to give instructions – first step, second step, and so on!
A recipe for making pancakes might begin with “First, melt butter. Second, warm some milk.” If we want something done quickly, we say “Do this first!” We use ordinal numbers while giving directions too – like “Take the third left down the street!”
We use ordinal numbers in titles of kings and queens: King Charles the First, or Queen Elizabeth the Second. We also use them when writing dates! For instance, Fourth of July or January 10th. We even find ordinal numbers in idioms! For example, to complete your homework at the Eleventh Hour means to do it just before you have to submit it!
Ordinal Numbers Worksheet:
Q: “The crocodiles snapped at the boat.” What are the third and sixth words in this sentence?
A: Snapped, boat.
Q: Write both forms of ordinal numbers for the following: 2, Eight, 12, Twenty, Thirty-One, 85, One Hundred.
A: Second (2nd), Eighth (8th), Twelfth (12th), Twentieth (20th), Thirty-First (31st), Eighty-Fifth (85th), One Hundredth (100th).