# Doubling and halving strategies

In this lesson, we will explain and model mental strategies for doubling and halving by using our understanding of multiplication and division. We will also use our doubling and halving strategies to multiply and divide by four and eight. By the end of this lesson, we would hope that everyone will be confident in explaining how to multiply and divide by four and eight by using strategies of doubling and halving.

Quiz:

# Intro quiz - Recap from previous lesson

Before we start this lesson, let’s see what you can remember from this topic. Here’s a quick quiz!

Q1.Look at the value represented by the place value grid below. If I multiply the number by 100, what will the new product be? 1/5

Q2.In mathematics, we use the term 'product' regularly. Look at the following calculation and identify which of the numbers listed would be classified as the product. 30 x 2 x 10 = 600

2/5

Q3.Which of the facts can I derive from the representation below? 3/5

Q4.Using the area model below, can you identify which of the number sentences is correct? 4/5

Q5.When multiplying and dividing, we regularly use the terms 'greater than' and 'less than'. Which of the following statements has used the symbols incorrectly?

5/5

Quiz:

# Intro quiz - Recap from previous lesson

Before we start this lesson, let’s see what you can remember from this topic. Here’s a quick quiz!

Q1.Look at the value represented by the place value grid below. If I multiply the number by 100, what will the new product be? 1/5

Q2.In mathematics, we use the term 'product' regularly. Look at the following calculation and identify which of the numbers listed would be classified as the product. 30 x 2 x 10 = 600

2/5

Q3.Which of the facts can I derive from the representation below? 3/5

Q4.Using the area model below, can you identify which of the number sentences is correct? 4/5

Q5.When multiplying and dividing, we regularly use the terms 'greater than' and 'less than'. Which of the following statements has used the symbols incorrectly?

5/5

# Video

Click on the play button to start the video. If your teacher asks you to pause the video and look at the worksheet you should:

• Click "Close Video"
• Click "Next" to view the activity

Your video will re-appear on the next page, and will stay paused in the right place.

# Worksheet

These slides will take you through some tasks for the lesson. If you need to re-play the video, click the ‘Resume Video’ icon. If you are asked to add answers to the slides, first download or print out the worksheet. Once you have finished all the tasks, click ‘Next’ below.

Quiz:

# Doubling and Halving Quiz

We looked at a range of mental strategies for doubling and halving quickly and efficiently today. Now it is time once again to demonstrate how much you can remember! Please read all questions carefully and take your time. Best of luck everyone.

Q1.The strategy of separating a number into its individual units of value is commonly known as?

1/5

Q2.Half of 24 is also the same as:

2/5

Q3.The bar model below is used to help divide or multiply numbers. What number should be placed in the top white boxes? 3/5

Q4.Which of the following number sentences will help you to solve the calculation 25 x 8?

4/5

Q5.Which derived fact helps me to mentally solve 240 ÷ 5?

5/5

Quiz:

# Doubling and Halving Quiz

We looked at a range of mental strategies for doubling and halving quickly and efficiently today. Now it is time once again to demonstrate how much you can remember! Please read all questions carefully and take your time. Best of luck everyone.

Q1.The strategy of separating a number into its individual units of value is commonly known as?

1/5

Q2.Half of 24 is also the same as:

2/5

Q3.The bar model below is used to help divide or multiply numbers. What number should be placed in the top white boxes? 3/5

Q4.Which of the following number sentences will help you to solve the calculation 25 x 8?

4/5

Q5.Which derived fact helps me to mentally solve 240 ÷ 5?

5/5

# Lesson summary: Doubling and halving strategies

## Time to move!

Did you know that exercise helps your concentration and ability to learn?

For 5 mins...

Move around:
Jog

On the spot:
Dance