Let’s continue our work with number lines and integers. This time, we’ll focus specifically on integer subtraction. The number line is a great tool to help us find solutions to problems as well as a great way to organize and represent our thinking.
The video shown at the top of the post has the entire visual progression of integer subtraction using number lines. However, I have chunked the video 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 for Integer Subtraction
Watch this video.
The first visual video prompt has 6 black squares and the viewer is asked to take away 3 red squares.
As we saw in previous integer videos, the viewer should already know that when you combine a black and red square, they disappear. This is an intuitive approach to the zero principle.
Therefore, adding 3 red squares and 3 black squares will introduce enough red squares to be subtracted as the question asks.
When we take away the 3 red squares, we are left with the 6 black squares we started with plus an additional 3 black squares for a total of 9 black squares.
The Act 1 Video shows another example, this time starting with red squares and taking away black squares.
After the viewer is shown how to tackle this visual prompt, a challenge is presented at the end of the Act 1 video as we head closer to the symbolic representation for positive and negative integers:
Act 3 Visual Video Silent Solution
Watch the Act 3 video to see the silent solution of the challenge.
Sequel Act 1 Video Visual Prompt
At the end of the Act 3 video, viewers are given a second challenge.
Sequel Act 3 Visual Video Silent Solution
Watch the Sequel Act 3 video silent solution.
How are you using these visual video prompts? Let us know in the comments and on social media!