Now, let’s do some math! How many squares are in the following image?
- (a)
- Did each member of your group come up with the same answer? Did each member come to their answer in the same way?
- (b)
- Pick one method and one answer from your group. Discuss this method in detail, as if you were presenting it to the class. What ideas are the most important? What steps are the most complicated?
- Compare and contrast these four explanations. What do they have in common? What is different about them?
- What do you like about the explanations? What do you dislike? Why?
- From this work, what can you determine that each student understands about this problem?
- What feedback would you give to each student to improve their explanation?
I counted 9 squares in the picture, and labeled them on the figure.
Explanation 3:
First, I remember that to be a “square”, you have to have the same length on both sides. The easiest squares to see are the tiny ones, and I can see three rows with three tiny squares in each of those rows for a total of nine tiny squares. The next easiest square to see is the biggest one: the entire picture is a square! Lastly, there are some medium-sized squares. Look at my picture to see an example. I found four of these medium-sized squares: two with their tops on the top row, and two with their bottoms on the bottom row. So, there are 14 total squares.
I’m convinced these are all of the squares in the figure, because the tiny ones are , the medium ones are , and the large one is , which is the entire original figure.
Explanation 4:
| Step | Why |
| We are looking for squares. | The problem tells us so. |
| Squares have the same length on both sides. | That’s what it means to be a square. |
| There are 9 tiny squares. | We count the squares. |
| There are 4 medium square. | We count the squares. |
| There is 1 big square. | We count the entire square. |
| There are 14 squares total. | We add up the squares we found. |