# Deriving addition and subtraction facts by using given calculations

In this lesson, we will be deriving addition and subtraction facts by using given calculations, considering how the whole or parts have changed and the impact this has on the new calculation.

# 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.

# Lesson summary: Deriving addition and subtraction facts by using given calculations

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The next lesson in Addition and subtraction is "Choosing appropriate addition strategies"