# 3.01 Repeated addition as multiplication

Lesson

## Ideas

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}

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

### Examples

#### Example 2

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

#### MA2-6NA

uses mental and informal written strategies for multiplication and division