1. Cardinal Numbers Vs.
Ordinal Numbers
Cardinal numbers and ordinal numbers are two different types of numbers that serve distinct purposes in mathematics and language. Cardinal numbers indicate quantity, while ordinal numbers indicate position in a list or series.
Understanding the difference between the two is crucial for effective communication and accurate representation of numerical data.
Cardinal numbers can be thought of as counting numbers and are used to represent the quantity or number of items. They are the basic numbers we use in everyday life, such as one, two, three, four, and five.
These numbers are used for counting, labeling, and quantifying objects or concepts.
Ordinal numbers, on the other hand, denote the position or order of an element in a series. They are formed by adding a suffix to the cardinal numbers, such as 1st, 2nd, 3rd, 4th, and 5th.
Ordinal numbers are employed when we want to indicate the ranking, hierarchy, or sequence of elements in a list or a group.
2. Examples Of Cardinal Numbers
Cardinal numbers are the fundamental numbers used for counting and quantifying. Here are some examples of cardinal numbers:
These numbers represent the quantity or the numerical value of the objects or concepts they describe. Cardinal numbers are widely used in various aspects of life, from basic arithmetic calculations to complex mathematical equations.
3. Examples Of Ordinal Numbers
Ordinal numbers are used to indicate the position or rank of an element in a series. Here are some examples of ordinal numbers:
These numbers describe the order or sequence of objects or concepts. Ordinal numbers are commonly utilized in contexts such as competitions, rankings, dates, fractions, and lists.
4. Rules For Writing Ordinal Numbers
When writing ordinal numbers, there are specific rules to follow to ensure accuracy and consistency. The primary rule is to use the last two letters of the cardinal number as a guide for constructing the ordinal number suffix.
For cardinal numbers ending in:
– “one”, change the “e” to “s” and add “t” (e.g., one > 1st)
– “two”, change the “o” to “w” and add “nd” (e.g., two > 2nd)
– “three”, change the “e” to “ee” and add “rd” (e.g., three > 3rd)
– other digits (four, five, etc.), add “th” (e.g., four > 4th, five > 5th)
By following these rules, ordinal numbers can be correctly formed and written out.
5. List Of Ordinal Numbers From 1st To 20th
To provide a comprehensive list of ordinal numbers, here they are from 1st to 20th, both written out and in digits:
1st, 2nd, 3rd, 4th, 5th, 6th, 7th, 8th, 9th, 10th, 11th, 12th, 13th, 14th, 15th, 16th, 17th, 18th, 19th, 20th
These ordinal numbers represent the corresponding positions or ranks in a series, highlighting the specificity and order of the elements they describe.
6. Usage Of st, nd, rd, And th In Ordinal Numbers
The usage of st, nd, rd, and th in ordinal numbers follows a pattern. Here’s how it works:
 Numbers 1st, 2nd, and 3rd deviate from the usual pattern and use st as the suffix. – Numbers from 4th to 20th (and beyond) follow the general rule and use th as the suffix.
This pattern ensures consistency and simplicity when constructing ordinal numbers, especially when dealing with larger numbers.
7. Special Cases With st, nd, And rd
While most ordinal numbers straightforwardly follow the pattern, there are a few exceptions worth noting. These exceptions occur when the numbers end in 1, 2, or 3 and are not part of the first three (1st, 2nd, and 3rd).
In these cases:

Numbers like 21st, 31st, and 41st continue with st (twentyfirst, thirtyfirst, fortyfirst). – Numbers like 22nd, 32nd, and 42nd continue with nd (twentysecond, thirtysecond, fortysecond).

Numbers like 23rd, 33rd, and 43rd continue with rd (twentythird, thirtythird, fortythird).
This deviation is due to the unique endings of these numbers and ensures proper pronunciation and written representation.
8. Using th For The Remaining Numbers
After the exceptions discussed in the previous section, all subsequent ordinal numbers from 24th, 34th, 44th, and so on, continue with th. This simplification provides consistency and avoids the need for additional alterations based on the individual number endings.
With the general rule of using th, the remaining ordinal numbers beyond the special cases can be easily constructed and represented, allowing for efficient communication and comprehension.
In conclusion, cardinal numbers represent quantity, while ordinal numbers indicate position or rank. Understanding the rules for writing ordinal numbers, including the special cases with st, nd, rd, and the usage of th for the remaining numbers, is essential for precise communication and accurate representation of numerical information.
Knowing these distinctions and following the proper formatting ensures clarity and coherence in both mathematical and linguistic contexts.