The ordinal numbers They are a type of numbers used to express the position or order of one or more elements within a succession or sequence. Unlike cardinal numbers, which are used to count the number of elements, ordinal numbers answer the question where? o in what order?A classic example would be in a race: the first to arrive is the winner, the second is the runner-up, and so on.
Ordinal numbers vs. cardinal numbers
It is important to establish the difference between Cardinal numbers y ordinal numbersCardinal numbers are those that indicate quantity, such as 1, 2, 3… While ordinal numbers indicate relative position in a list or sequence, such as first, second, third, etc.
For example, on a shelf with five books:
- Cardinal number: There are five books on the shelf.
- Ordinal number: The third book is my favorite.
The importance of using one or the other correctly lies in the clarity of the information. Cardinal numbers tell us how many elements there are, while ordinal numbers tell us about the exact position of each element.
How are ordinal numbers written?
Ordinal numbers, in addition to being written in letters such as First of all, second o third, have a symbolic representation that differentiates them from the cardinals. This symbol is the degree sign (º), which is placed to the right of the number. For example: 1 º, 2 º, 3 º.
For feminine ordinal numbers, the letter is used a in a flutter to denote gender, as happens in primera (1a), second (2a).
For numbers beyond tenths, the most common way is to use the cardinal number followed by the corresponding symbol, such as: 21 º for the twenty-first.
Structure and suffixes of ordinal numbers
Ordinal numbers in Spanish use different suffixes depending on their position in the sequence. These suffixes are some of the most common:
- -I was/was: Used for the first ordinal numbers, such as First of all (1 º) or third (3 º).
- -to/ta: Common in middle ordinals, such as fifth (5 º), sixth (6 º).
- -eno/ena: This suffix has fallen into disuse except in the case of nineth (9 º).
- -avo/ava: Used exclusively for fractions, such as one tenth (1/10).
In addition, some ordinal numbers may be abbreviated in a particular way. For example, First of all can be abbreviated as 1 ºWhile second is abbreviated 2 º. If these are feminine numbers, then the abbreviation would be 2a to second.
Exceptions in the use of ordinals
There are certain rules that we must take into account to avoid common errors when using ordinal numbers. An example of this is when the terms First of all y third before a noun. In these cases, both ordinal numbers lose their last vowel: we say the first train and not him first train, and the third step instead of the third step.
How to convert a cardinal number to an ordinal number
To transform any cardinal number into an ordinal number, we can simply add the degree sign (º) after the number:
- The number a (1) becomes First of all (1º).
- The number two (2) becomes second (2º).
- The number three (3) becomes third (3º).
If we want to write it in letters, it is a matter of learning the ordinal names. Starting from the twelfth, it is common to use cardinal numbers in combination with the degree sign, such as 23 º o 45 º.
Examples of ordinal numbers
Let's look at some examples to understand how ordinal numbers are used in everyday life:
- Home competition: The winner takes the First.
- Second day: Today is the The second day of the week.
- Tenth anniversary: We celebrate the tenth anniversary.
Ordinal numbers from 1 to 1000
Below is a list of the most common ordinal numbers, explaining their use in different situations:
- 1st First / 1st First
- 2nd Second / 2nd Second
- 3rd Third / 3rd Third
- 4th Quarter / 4th Quarter
- 10th Tenth / 10th Tenth
- 20th Twentieth / 20th Twentieth
- 50th Fiftieth / 50th Fiftieth
- 100th Hundredth / 100th Hundredth
This list can be extended much further, but the examples above cover the most commonly used ones in everyday life.
Correct use of ordinal numbers is essential for clear communication, especially when we are talking about the position of elements in a sequence. Just as cardinal numbers allow us to count, ordinal numbers allow us to order, which is vital in both mathematics and everyday language.