Subitize this!

In very young children, right-brain dominancy gives the ability to “subitize” large quantities. Wikipedia defines subitizing as a “rapid, accurate and confident judgment of number.” This is something we can all do up to a small number of items – usually around 4 or 5. The maximum number of items most adults can subitize is around 10 to 12 (although it will typically take longer to do so, and the person will feel less confident doing it). After that, you’re either guessing or counting.

When a very young child looks at a large number of items, she doesn’t need to guess or count to see how many are there. The child can instantly see 48 marbles, in just the same way that the rest of us can instantly see 4 – by subitizing. The only thing the child doesn’t know, however, is how to tell us what she sees. She doesn’t know that this number is called “forty-eight.” In other words, the labels for quantities are what we need to teach the child.

Once the child has a foundation in quantity (having learned up to at least the number 20), you can begin equations using those quantities (while continuing to teach up to 100). Children taught in this way should soon be able to do instant math. Parents will typically present an addition, subtraction, multiplication or division problem, and then provide two or three dot cards from which the child can choose the solution. An example of children taught by the Doman method doing instant math can be seen in the following video (at 5 minutes, 26 seconds).

The ability to subitize large quantities will typically fade away as a child grows older. The exact age at which children lose this ability varies from person to person. However, it is safe to say that children retain the ability to perceive large quantities at least up to the age of two and a half.

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The reality of numbers…