The Cardinal Numbers: How to Teach Your Child to Count Sets and Match Them


One of the most important math skills kids need to master early in their schooling is that of counting sets. Counting teaches children the meaning of a number – that is, what the number represents in the real-world. They may have learned to recite the numerals in order, but they also need to learn how to apply this conceptual understanding of the number in meaningful situations. For example, knowing that there are five apples in a basket.

Counting the number of items in a set teaches children the concept of cardinality. Cardinality refers to the knowledge that the last item counted in the set represents the total number of items in it. This number is a cardinal property of that group of objects and will not change unless items are added or removed.

Understanding cardinality helps children compare sets and perform basic addition and subtraction on them. Since they would already know the numerals by heart, one approach to teaching sets would be to have them count sets and match them to the corresponding number.

Here are 4 simple activities to teach your child cardinality and how to match sets –

  1. Count the Sets and Match with Numerals

In this exercise, your child will practice counting the number of objects in a grouping and match them with the correct cardinal number.

Collect everyday items familiar to your child and group them in ones, twos, threes, and so on, with the largest being a group of ten. Place these items around your child on the floor/desk. Ask them to point to each type of item, name it out aloud, and count the number of objects in each grouping. If they make a mistake when counting, ask them to try again until they get it right.

Now hand the child a pad of sticky notes and a pencil. Ask them to write the numeral corresponding to the number of items in each group on a sticky note and put it on the desk next to the items. Repeat this until all the groups are correctly numbered.

Alternatively, you can download and print worksheets like the ones below for this activity.

  1. Groupings Objects into Sets

Present your child with a pile of objects of many different types (you could just scramble all the items from activity #1 into one big heap!). Have them remove items of a type from the pile and collect them into groups. Next, have them count the number of items in each group they have created and write the correct numeral next to them.

This activity helps them learn how to classify and sort objects into groups and then tag them with the cardinal numbers.

  1. Matching Picture Sets

For this activity, use a whiteboard and marker.

Plot a table with five rows and two columns. In each cell, draw a series of objects instantly recognizable to the child. Each row should have objects numbering between 1 and 5, with no two adjacent cells having the same number of items.

Show your child the first cell and ask them to name the object and count the number of items in the cell. Now ask them to choose a cell from the second column that has the same number of items as this cell. Repeat this for all rows in the first column.

This activity will further reinforce their learning by having them compare the cardinality of one group to that of another, performing basic operations using numbers.

  1. Matching Domino Tiles – And Playing the Game!

It’s time to step it up a notch!

Arrange a full set of dominoes in a row (28 tiles). Choose a tile. Ask your child to count the number of pips on each end of the tile separately and write it down. Now have them identify as many tiles as they can with the same number of pips for each end of the tile and place them next to the first tile.

Scramble the set and rearrange the tiles. This time, have the count the total number of pips on a tile and match it with other tiles that have the same number of pips overall.

Repeat this activity until all tiles are arranged in groups.

Tip: Once they have mastered counting and matching sets with the tiles, why not play a round? Teach them how to play the game of dominoes to strengthen their learning and give them a breather!

What activities do YOU use to teach your child counting sets and matching? Let us know in the comments below and we’ll feature it in our post.

And don’t forget to download the PlayAblo app or visit for more enjoyable learning games!


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