Many parents teach their children to count at an early age. However, it is not usually until they start school that children learn ordinal numbers. In part this is because they first need to understand the concept of quantity and have a good command of cardinal numbers before they understand what ordinal numbers are and what function they perform. To make your work easier, at the Infant Stage we explain what ordinal numbers consist of, what their nomenclature is, and we provide you with some educational tools that you can implement at home.

What are ordinal numbers?

In mathematics, ordinal numbers are those that denote the position of an element with respect to the rest, within the same set. While the cardinal numbers offer information about the number of elements that exist in a set, the ordinal numbers indicate the order or position they occupy within the group.

For example, they are used to classify the results of an athletics competition. In this way, the first to reach the finish line occupies the first position while the one before him occupies the second place and the following one, the third place. Likewise, ordinal numbers can be useful for numbering the floors of a building, indicating the location of people in a row, or naming anniversaries and recurring events. They are also used for dates, especially for the first day of each month.

How are ordinal numbers written?

Ordinal numbers have their own nomenclature. In mathematics, to convert a cardinal number into an ordinal number, you only need to add a flown letter, which is nothing more than a kind of superscript, to the right. In the case of the masculine a small circle is added while in the case of the feminine an “a” is used. Although it is often overlooked, as it is an abbreviation, a period must be added between the number and the flown letter, according to the Royal Spanish Academy of Language .

For example, the number 1 would be written 1st in masculine and 1st in feminine, the number 2 would be 2nd in masculine and 2nd in feminine while the number 3 would be 3rd in masculine and 3rd female, and so on.

However, when it comes to writing in letters, each ordinal number has its own name. The name not only denotes its position in the group, but also allows it to be related to its cardinal pair. For example, in the case of number 1, the ordinal would be first, for number 2 it would be second, for number 3, third, and so on. Based on their writing in letters, ordinal numbers can be considered simple or compound.

Simple ordinals are the numbers from 1 to 10, as well as those numbers that correspond to the tens, that is, from 20 to 90, and to the hundreds, from 100 to 900. Simple ordinals are also the numbers from 1000 that are formed adding the ending “th”. Meanwhile, the rest are considered compound ordinals and are written by juxtaposition or fusion of simple forms, as in the case of thirteenth or thirty-ninth.

Also, there are some special rules for writing ordinal numbers:

  • The first and third ordinals are shortened into the “first” and “third” forms when they precede a masculine noun, are part of compound ordinals, or come before an adjective. This, except when it comes to ordinals that accompany feminine nouns, in which case there is no variation.
  • The ordinals corresponding to the numbers 11 and 12 can be written in two ways, either eleventh and twelfth or eleventh and twelfth.
  • The ordinals of the first and second hundred can be written together or separately, as in the case of thirteenth or thirteenth. In this case, if they are written together they do not have an tilde, but if they are written separately they do keep the tilde.

3 simple activities to teach children ordinal numbers

Learning ordinal numbers by heart can be boring and monotonous. On the other hand, if you use fun educational activities to teach children ordinal numbers, you will not only arouse their interest and curiosity, but you will also help them learn them sooner and better. Here are some ideas you can put into practice at home:

1. Use the rankings

A simple and fun way to motivate children to learn ordinal numbers is to ask them to classify different sets according to the position of their elements. Whether it’s a box of toys, the shoes in the closet or cards with different outfits, the idea is that the little ones order the elements according to the ordinal sequence.

2. Make the game your ally

Children love to have fun, so they will surely love to be entertained while coloring using only the third, fifth and sixth colors from the box. They can also play a game of colliding marbles according to their position, for example, the third and fifth from the wall. And, for those who like to tell stories, another idea is to encourage them to create a story with the third and fourth toys on the shelf as the protagonists.

3. Identify ordinals in practice

Using examples from everyday life for children to practice ordinal numbers will not only help them to reinforce them but also to discover their usefulness. If you are in the supermarket, you can ask your children what position you occupy in the line or if you are cooking at home, you can ask them to reach you the second glass from left to right. The idea is that they become familiar with ordinal numbers through small daily actions.

The main ordinal numbers

  • 1st – first
  • 2nd – second
  • 3rd – third
  • 4th – fourth
  • 5th – fifth
  • 6th – 6th
  • 7th – seventh
  • 8th – 8th
  • 9th – 9th
  • 10th – 10th
  • 11th – eleventh / eleventh
  • 12th – twelfth / twelfth
  • 13th – thirteenth
  • 14th – fourteenth
  • 15th – fifteenth
  • 16th – sixteenth
  • 17th – seventeenth
  • 18th – eighteenth
  • 19th – 19th
  • 20th – twentieth
  • 21st – twenty-first
  • 22nd – twenty-second
  • 23rd – twenty-third
  • 24th – twenty-fourth
  • 25th – twenty-fifth
  • 26th – 26th
  • 27th – twenty-seventh
  • 28th – twenty-eighth
  • 29th – twenty-ninth
  • 30th – thirtieth
  • 40th – fortieth
  • 50th – fiftieth
  • 60th – sixtieth
  • 70th – seventieth
  • 80.º – octogesimo
  • 90th – ninetieth
  • 100th – hundredth
  • 101st – one hundred and one
  • 200.º – two hundredth
  • 300.º – tricentésimo
  • 400th – four hundredth
  • 500.º – five hundredth
  • 600.º – six hundred
  • 700th – seven hundredth
  • 800.º – eight hundred
  • 900th – nine hundredth
  • 1000th – thousandth
  • 2000th – two thousandth
  • 100000th – one hundred thousandth
  • 1000000th – millionth