Topics
3. Multiplication strategies
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Australia
Year 4

3.06 x6

Lesson
Practice
Lesson

Are you ready?

Multiplication looks at equally sized groups. Can you solve this problem?

Examples

Example 1

Find the value of 3\times 9.

Worked Solution
Create a strategy

We can think of 3 \times 9 as 3 groups of 9 like in the image below that has 3 groups of 9 squares:

The image shows 3 rows of 9 squares.
Apply the idea

The above image has 27 squares in total.

\displaystyle 3\times9\displaystyle =\displaystyle 27
Idea summary

Multiplying by three is the same as tripling and can be thought of as the total of three equally sized groups.

Multiply numbers by 6

Let's look at how to multiply numbers by 6.

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Examples

Example 2

Find the value of 6\times3.

Worked Solution
Create a strategy

We can think of 6\times 3 as 6 groups of 3 just like in the image below that has 6 groups of 3 squares:

The image shows 6 rows of 3 squares.
Apply the idea

The above image has 18 squares in total.

6 \times 3 = 18

Reflect and check

We can also multiply the number by 3 then double the answer:

\displaystyle 3\times 3\displaystyle =\displaystyle 9Multiply by 3
\displaystyle 2\times 9\displaystyle =\displaystyle 18Double the answer
Idea summary

You can use a doubling strategy to multiply a number by 6. Start by multiplying the number by 3, then double the answer.

Outcomes

ACMNA074

Investigate number sequences involving multiples of 3, 4, 6, 7, 8, and 9

ACMNA075

Recall multiplication facts up to 10 × 10 and related division facts

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