Topics
3. Multiplication and division
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Level 5

3.01 Repeated addition

Lesson
Practice
Lesson

Are you ready?

Can you remember another way to write a problem like 3+3+3+3, which is called  repeated addition? 

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

In this video we see how adding the same number over and over is the same as multiplication.

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Examples

Example 2

Answer the following:

a

Write this addition as a multiplication: 12+12+12+12+12+12+12+12

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 8 groups of 12. We can rewrite this as multiplication: 12+12+12+12+12+12+12+12=8\times 12

b

Find the value of 8 \times 12.

Worked Solution
Create a strategy

Use skip counting or a multiplication table.

Apply the idea

By skip counting by 12 eight times, we have:12, \,24, \,36, \,48, \,60, \,72, \,84, \,96

8 \times 12=96

Idea summary

If we add something over and over, it's like having many groups of that number. When we have groups of something, we call that multiplication, and we use \times for multiplication.

6+6+6+6+6 is the same as 5 groups of 6, or 5 \times 6.

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