Kidaptive Blog

Right on the button: Understanding cardinality

, September 27, 2014

Want a quick and easy way to determine how well your child understands cardinality? (Cardinality refers to the number of items in a set and is fundamental to basic math operations like addition and subtraction!)

All you need is a table, a small towel or napkin, and at least ten small items, such as buttons.

1. Put the buttons in a container that you can hold on your lap.

2. Lay the towel on the table and place any number of buttons underneath it so your child can’t see them. Then invite your child to play a guessing game with you.

3. Lift your side of the towel and count the buttons aloud, without using any gestures or motions.

4. Once you’re done counting, ask your child, “How many buttons are there under the towel?”

5. Whatever number your child says, lift the towel and count the buttons together to check. If your learner is correct, this process helps confirm the right answer so the two of you can celebrate. If your child answered with a different number or didn’t respond at all, do the count together and then state the cardinal value explicitly. For example, you can say, “one…two…three…four…five! There were five buttons.”

Play a few times using a variety of numbers from zero to ten (or more). Keep in mind that it may seem obvious to you that the number of buttons you count aloud is the number your child should say are under the towel. But it actually isn’t obvious to young children who are just learning about cardinality. As children learn number words, they learn them in many ways: things in a sequence, labels for an item during counting, or names for the written symbols they see. But it takes time to integrate all of that into knowing that a number word in the context of a set represents the quantity of things counted. So practice is key!

We would love to hear your thoughts on this activity, as well as suggestions on future topics to cover! Please leave a comment.