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Watch this Teacher Talk and discover how to add three 1-digit numbers together using number bonds.

Here is a calculation with three numbers being added:

5 + 4 + 1 = 10

If the numbers are written in a different order, what happens to the answer?

4 + 5 + 1 = 10

What about another order?

1 + 4 + 5 = 10

We say that addition is commutative because whichever order we add the three numbers, the answer is the same.

Let's try another calculation.

6 + 2 + 1 = 9

Now let's change the order.

6 + 1 + 2

What about this?

1 + 2 + 6?

The total is 9 for all these sums, the numbers have just been added in a different order.