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Watch: Adding three one-digit numbers

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

Girl asking a question

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.

Girl asking a question
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Example

Character and a question mark

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.

Character and a question mark
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Activity 1

Joe walks 3 km from home to school, then 4 km from school to Sophie's house, then 2 km from Sophie's house back home.

(i) How far does he walk altogether doing that journey?

(ii) If Joe walked from home to Sophie's house then to school and then back home, how far does he walk?

Map showing joe's house
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Activity 2

8 + 4 + 3 = 15

Can you find three other ways to add these numbers to make 15?

A question mark
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Quiz

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NEW! Play Guardians: Defenders of Mathematica - the winter update
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