In this video, we introduce the idea of subtracting integers by using simple subtraction of a positive by a positive (black squares) and negative subtracting a negative (red squares). We then offer a notice and wonder situation when we give black squares, followed by the introduction of a black and red (the zero principle).

Viewing the previous two posts would be useful for students to have the full understanding of the zero principle. Access them here and here.

Once students watch the introductory video above, show them this video:

Here, we try to do the opposite of what was happening in the previous two posts. Instead of combining a red and a black and having them disappear, we are having a red and black appear before subtracting one of the two colours.

Still not sure what is going on here? No problem! Check out the visual prompts below…

Use the following visual prompts to help students to conceptualize the addition and subtraction of integers.

Math is visual. Let’s teach it that way!

Math Is Visual Prompts

Feel free to use the video and pause in-between ideas or alternatively, use the following visual prompts.

Visual #1 Prompts

Show the following image:

Subtracting Positive and Negative Integers Visual Prompts 01 - 8 - 3

You may consider working only with the visual prior to introducing the numerical symbols included in the visual below:

Subtracting Positive and Negative Integers 1a - 8 black minus 3 black

After giving students some time to determine how many squares will remain and what colour they will be, you can show them the visual that matches this scenario.

Subtracting Positive and Negative Integers 1b - 8 black minus 3 black equals 5 black v2

Visual #2 Prompts

Show the following image:

Subtracting Positive and Negative Integers Visual Prompts 04 -9 - -2

After students use square tiles and come to their conclusion, have them write out their thinking using a numerical expression.

Then, show them this:

Subtracting Positive and Negative Integers 2a - 9 red minus 2 red

And finally, a simplified version:

Subtracting Positive and Negative Integers 2b - 9 red minus 2 red equals 7 red v2

Visual #3 Prompts

Show the following image:

Subtracting Positive and Negative Integers Visual Prompts.007

After students use square tiles and come to their conclusion, have them write out their thinking using a numerical expression.

Then, show them this:

Subtracting Positive and Negative Integers 3a - 9 black minus 2 red

And finally, visuals for the simplification:

Subtracting Positive and Negative Integers 3b - 9 black minus 2 red plus 2 black plus 2 red

Subtracting Positive and Negative Integers 3c - 9 black minus 2 red equals 11 black 2

 

Visual #4 Prompts

Show the following image:

Subtracting Positive and Negative Integers Visual Prompts.017

After students use square tiles and come to their conclusion, have them write out their thinking using a numerical expression.

Then, show them this:

Subtracting Positive and Negative Integers 5a - 7 red minus 3 black

And finally, a simplified version:

Subtracting Positive and Negative Integers 5b - 7 red minus 3 black plus 3 black plus 3 red

Subtracting Positive and Negative Integers 5c - 7 red minus 3 black equals 10 red v2

 

kylepearce3

View all posts

Add comment

Your email address will not be published. Required fields are marked *

Categories

Get Notified When New Content Is Added!

* indicates required
%d bloggers like this: