Applying mental calculation strategies to adding and subtracting decimals

In this lesson we will use a range of informal mental strategies to add and subtract decimal numbers.

This quiz includes images that don't have any alt text - please contact your teacher who should be able to help you with an audio description.

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.True or False: 1.356 - 0.999 = 0.356

1/4

Q2.True or false: 134.76 - 82.5 = 52.76

2/4

Q3.True or false: 24.56 - 19.9 = 4.66

3/4

Q4.True or false: 46.78 - 3.8 = 42.99

4/4

This quiz includes images that don't have any alt text - please contact your teacher who should be able to help you with an audio description.

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.True or False: 1.356 - 0.999 = 0.356

1/4

Q2.True or false: 134.76 - 82.5 = 52.76

2/4

Q3.True or false: 24.56 - 19.9 = 4.66

3/4

Q4.True or false: 46.78 - 3.8 = 42.99

4/4

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.

This quiz includes images that don't have any alt text - please contact your teacher who should be able to help you with an audio description.

Quiz:

Applying mental calculation strategies when adding and subtracting decimals

Fantastic work finishing today's lesson! Put your mental strategies to the test and solve these decimal equations.

Q1.6.3 + 12.27

1/6

Q2.2.89 - 1.41 =

2/6

Q3.7.3 + 7.2 =

3/6

Q4.2.671 + 5.999

4/6

Q5.4.53 - 4.49

5/6

Q6.1.82 + 4.08

6/6

This quiz includes images that don't have any alt text - please contact your teacher who should be able to help you with an audio description.

Quiz:

Applying mental calculation strategies when adding and subtracting decimals

Fantastic work finishing today's lesson! Put your mental strategies to the test and solve these decimal equations.

Q1.6.3 + 12.27

1/6

Q2.2.89 - 1.41 =

2/6

Q3.7.3 + 7.2 =

3/6

Q4.2.671 + 5.999

4/6

Q5.4.53 - 4.49

5/6

Q6.1.82 + 4.08

6/6

Lesson summary: Applying mental calculation strategies to adding and subtracting decimals

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