K-2: shapes, counting, area
I’m excited to share with you my latest Family Math Night Collaborative Project: Space Invaders. Here’s a photo of the final result. (There are actually 3 aliens to choose from in the lesson plan. This is alien #1).
Here’s some of the background information I include in the lesson plan:
Pixels are small single-colored squares that make up images in computer graphics. These pixels are displayed as a bitmap, a rectangular matrix of dots. These pixels, sometimes called dots, are each assigned a specific color and are arranged along the horizontal axis (x-coordinate) and vertical axis (y-coordinate) of the matrix.
Computer graphics have come a long way in the last decade and look much more sophisticated today than they did back in 1978. But back when graphics were first being designed on computers, they had a “boxy” look. That’s because the screen displays (screen resolutions) were not as good as they are today.
Note: For the purpose of this activity, each pixel does not need to be represented by a single color.
Some of you may know that I always put together a video of my collaborative projects describing in detail how to do the activity and offering additional tips. I’ve included the video below for you.
Primary students (K-2): shapes, counting, repeated addition, area
Intermediate students (3-5): classifying quadrilaterals, area model of multiplication, multiplication, prime, composite, and square numbers
For this one, I represented each number as a rectangular array. I also color-coded the arrays hoping that students would notice the relationship between the colors and the arrays that went with them. Notice how the orange arrays are square numbers. The red arrays are our prime numbers. Then I used blue for arrays that were non-square and had a length of two. Purple was non-square with a length of three.
I was also hoping that students would notice that some numbers were represented by more than one array (composite numbers). Prime numbers had only one array. Note: ‘1’ is not a prime number which is why I colored it orange – the color of the square numbers.
This activity does a nice job of visually reinforcing the area model of multiplication: L x W = A
Sample Student Responses
So for this What Do You Notice? poster, I decided to tie in rectangular arrays with prime and composite numbers. That said, whatever math-y thing students notice is totally acceptable. For example, one student noticed that the “buildings” had square windows. Great. That’s a little bit of geometry. Another student noticed that each set of colored rectangles included the same number of squares. Again, great, as that required some counting and comparison. Just like the student who noticed that there are more yellow squares than any other color square.
As far as the prime and composite numbers…yep, we got that covered, too! Here’s how David described it on his post-it, “The first 3 are composite, the last 2 are prime. There are different arrays for each number.” And he’s right. The composite numbers have more than one rectangular array while the prime numbers only have one array.
But here’s an observation I totally didn’t notice. “The columns go one higher, one lower.” And, indeed, they do!