# Ordinal Numbers – Definition, FAQs, Practice Problems, Examples

Home » Math-Vocabluary » Ordinal Numbers – Definition, FAQs, Practice Problems, Examples

## What are Ordinal Numbers?

Numbers that are used to represent the rank or position of an object or a person are known as ordinal numbers. They are also referred to as positioning or ranking numbers.The sequence of ordinal numbers vary on the parameters that are based on the positions that are defined, such as weight, height, marks, size, etc. Such numbers are also known as ordinals.

## How to Write Ordinal Numbers?

Ordinal numbers or ordinals are written using numerals as prefixes and adjectives as suffixes.

For example, 1st, 2nd, 3rd, 4th, 5th, 6th, 7th, 8th and so on. We can easily identify an ordinal number: it talks about positioning.

So, if we were to say, “Bring me the bottle of jam that is lying on the 4th shelf.”, one would know that the ordinal number here is 4, which informs us about the position of the jam bottle.

The above picture shows different floors of a building. Here, we can use ordinal numbers to define the position of the floors.

The numbers 1st (first), 2nd (second), 3rd (third), 4th (fourth), 5th (fifth), 6th (sixth), 7th (seventh), 8th (eighth), 9th (ninth) and 10th (tenth) tell us about the positions of various floors in the building. Therefore, all of them are the ordinal numbers.

## Applications of Ordinal Numbers

Ordinal numbers are a great way to talk about the order of something. For example, the order of dates. These numbers are only used when data is provided and the data is to be arranged in order.

For example: Someone who has performed well throughout the year may get the chance to be valedictorian. They would be first in line. But someone who performed well, but was unable to score as much as the person before in various tests and exams, may be second in line to be valedictorian. The person who has not performed well at all, has the least amount of chance.

The picture given below shows some athletes competing in a 500-m race. We can also use ordinal numbers to define their positions in order to see who the winner and runners-up of the race are.

Other examples of ordinal numbers are as follows:

• Jennifer always ranks 2nd in the class.

Here 2nd is the ordinal number that tells you about the position that Jennifer has secured.

• Jane is standing at the 5th place in the queue.

Hereby the ordinal number is 5th, we understand Jane’s position in the queue.

• Jenny came 3rd in the race.

Here, 3rd is the ordinal number which tells you about the place that Jenny has secured in the race.

• The 10th table is reserved.

Here, the ordinal number 10th refers to the number of table reservations made.

## Ordinal Numbers v. Cardinal Numbers

The type of  numbers that are used for counting the number of objects or persons are known as cardinal numbers. This type of numbers are used for representing the cardinality of the number of elements in a set.

Cardinality means to know about the number of elements in a set.

Cardinal numbers can be the natural numbers that we use while we are counting like one, two, three, four, five and so on.

On the other hand, ordinal numbers are used to determine the rank or position of any object or person. We write ordinal numbers using numbers as prefixes and adjectives as suffixes.

Let us understand the difference with the help of an example.

Some students were asked to collect marbles.

Tom collected 1, Jane collected 2, and Clove collected 3 marbles.

Here the numbers 1, 2, 3 are cardinal numbers as they represent the quantity of marbles.

Now, the one who scores maximum wins. So, Clove stands 1st, Jane stands 2nd and Tom stands 3rd.

Here the numbers 1st, 2nd and 3rd are ordinal numbers as they represent the position of the students.

## Ordinal Numbers v. Nominal Numbers

A set of numbers that are used for labeling certain items or places so that they can be identified easily are known as nominal numbers. Whenever we have to identify an object uniquely, we use nominal numbers. These numbers are not of much use because they are just going to give information about location and not about its quantity, quality, etc. Nominal numbers can be used as area codes, on number plates of vehicles, etc. Operations such as addition, subtraction, multiplication and division are meaningless on nominal numbers.

For example: In a phone number like 202 588-6500, the number is a nominal number. Even if we apply an operation, it will not give us anything meaningful.

On the order hand, the ordinal numbers tell us about the rank or position of any object or person.

For example: Sophia lives in the 34th house on San Pablo Avenue, California.

## Fun Fact!

11, 12 and 13 are the only numbers to use a suffix ‘–th’ but all other numbers ending with 1 use ‘–st’, those ending with 2 use ‘–nd’ and those ending with 3 use ‘–rd’.

## Solved Examples On Ordinal Numbers

Example 1: Which English alphabet is 12th from the beginning?

Solution: The alphabet that is 12th from the beginning is L.

Example 2: Kim, Kethy, Kiah and Kaina are sitting in the line in alphabetical order. What is the position of Kiah from the beginning?

Solution: According to alphabetical order, the order in which they’re sitting would be: Kaina, Kethy, Kiah, Kim. So, Kiah is at the 3rd position.

Example 3. Christmas lies on the _____ of December.

Solution: Christmas lies on the 25th of December.

## Practice Problems On Ordinal Numbers

1

### Which one of the following denotes an ordinal number?

The vehicle number of Sarah is KL23AB89.
There are 9 apples on the tree.
Catheline came 4th in the drawing competition.
None of these
CorrectIncorrect
Correct answer is: Catheline came 4th in the drawing competition.
In the option C, the number 4th is telling about the position of Catheline in the drawing competition.
2

### How do you write 51 in ordinal numbers?

51
51st
51th
51rd
CorrectIncorrect
The ordinal number for 51 for 51st.
3

### In the word, “COMPENSATION”, which are the fourth and tenth letters?

M and O
M and N
P and I
E and O
CorrectIncorrect
Correct answer is: P and I
The fourth letter is P and the tenth letter is I.

## Frequently Asked Questions On Ordinal Numbers

No, we cannot write 0 as an ordinal number.

Exceptional ordinal numbers are the ordinal numbers that do not end with -th. For example: 1st (first),  2nd (second), 3rd (third), etc.

Ordinal numbers were invented by Georg Cantor in 1883.