Integer Addition Using Number Lines

In yet another video focusing on addition and subtraction of positive and negative integers, we introduce a number line as a tool to help organize our thinking.

The video shown at the top of the post has the entire visual progression. However, the video is chunked into smaller pieces below which might be more useful when actually using with your students or your children at home.

Act 1 – Introducing the Number Line With Integers

Watch this video.

In the video, the viewer is introduced to black and red squares (as we were in previous integer videos) and should already know that when you combine a black and red square, they disappear. This is an intuitive approach to the zero principle.

Rather than simply having individual pairs of black and red squares combining and going away, we choose to model the black squares on a number line from 0 to 11. Then, we line up the red squares (intentionally giving less than the black at first) to cancel with the same amount of black squares.

Leaving us with only 3 black squares remaining.

The same video also shows a second strategy, lining up the red squares from the rightmost black square so that the remaining 3 black squares will be left beginning at 0 on the number line.

Act 1 Visual Video Prompt

At the end of the act 1 video, the viewer is challenged with this question.

Act 3 – Visual Video Solution

Watch this act 3 visual video prompt solution to see an animated solution on the number line to the previous challenge.

At the end of the video, the viewer is introduced to a sequel challenge.

Sequel, Act 1 – Another Challenge

Viewers are encouraged to think through this task delivered at the end of the previous visual video prompt.

While it might not be obvious now, but since there are more red squares than black, we will be left with red squares. This will create the need for us to consider how we might show how many red squares are left on a number line.

Here’s a video snippet that takes you up to that point.

And a visual video prompt.

While I could post screenshots, I don’t want to ruin it. You’ll have to watch.

Sequel, Act 3 – Visual Video Solution

Check out how I’ve tried to scaffold the introduction of negative values on the number line.

The approach might bend a few folks out of shape for a bit, but don’t worry… we’ll handle things more traditionally in the next couple posts.

How are you using these visual video prompts? Let us know in the comments and on social media!