Topics
3. Multiplication strategies
topic badge
Australia
Year 4

3.01 Repeated addition as multiplication

Lesson
Practice
Lesson

Are you ready?

Can you write a repeated addition as a multiplication number sentence?

Examples

Example 1

Write this addition as a multiplication. 3+3+3+3+3+3

Worked Solution
Create a strategy

We can rewrite the addition as a multiplication using: \text{Number of groups}\times\text{Amount in each group}

Apply the idea

We have 6 groups of 3. We can rewrite this as multiplication: 3+3+3+3+3+3=6\times 3

Idea summary

We can rewrite the addition as a multiplication using: \text{Number of groups}\times\text{Amount in each group}

Repeated addition

Let's use what we know about writing repeated addition as multiplication number sentences and use it to solve questions as well.

Loading video...

Examples

Example 2

Answer the following:

a

Write this addition as a multiplication:\,\, 4+4+4+4+4

Worked Solution
Create a strategy

We can rewrite the addition as a multiplication using: \text{Number of groups}\times\text{Amount in each group}

Apply the idea

We have 5 groups of 4. We can rewrite this as multiplication: 4+4+4+4+4=5\times 4

b

Find the value of 5 \times 4.

Worked Solution
Create a strategy

Use skip counting or a multiplication table.

Apply the idea

By skip counting by 4 five times, we have4, \,8, \,12, \,16, \,20

So, 5 \times 4=20.

Idea summary

If we are adding groups of the same size, we can also write it as a multiplication:

\text{Number of groups}\times\text{Amount in each group}

To find the answer we can use skip counting or a multiplication table.

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

ACMNA081

Explore and describe number patterns resulting from performing multiplication

What is Mathspace

About Mathspace