## An Example of “Doing Mathematics”: Creating Voronoi

I’ve been thinking a lot about how we look at academic standards (what we call curriculum expectations here in Ontario) lately.  Each person who reads a standard seems to read it through their own lens.  That is, as we read a standard, we attach what we believe is important to that standard based upon our prior experiences.  With this in mind, it might be worth looking at a few important parts of what makes up a standard (expectation) in Ontario.  Each of our standards have some/all of the following pieces:

• Content students should be learning
• Verbs clearly indicating the actions our students should be doing to learn the content and demonstrate understanding of the content
• A list of tools and/or strategies students should be using

Each of these three pieces help us know both what constitutes understanding, and potentially, how we can get there. However, while our standards here in Ontario have been written to help us understand these pieces, many of our students experience them in a very disconnected way.  For example, if we see each expectation as an isolated task to accomplish, our students come to see mathematics as a never-ending list of skills to master, not as a rich set of connections and relationships.  There are so many standards to “cover” that what ends up being missed for many students is the development of each standard. The focus of teaching mathematics ends up as the teaching of the standards instead of experiencing mathematics.  We give away the ending of the story before our students even know the characters or the plot. We share the punchline without ever setting up the joke.  We measure our students’ outcomes without considering the reasoning they walk away with… while many students might be able to demonstrate a skill after some practice, it’s quite possible they don’t know how it’s helpful, how it relates to other pieces of math, and because of this, many forget everything by the next time they use the concepts the next year.

To help us think deeper about what it means to experience mathematics from the students’ point of view, Dan Meyer has been discussing building the “intellectual need” with his whole “If Math Is The Aspirin, Then How Do You Create The Headache?”.  Basically, the idea here is that before we teach the content that might be in our standards, we need to consider WHY that content is important and how we can help our students construct a need for the skill.  He has helped us think about how our students could experience the long-cut before our students ever experience the short-cut.

Let’s take a specific example of a specific standard:

construct perpendicular bisectors, using a variety of tools (e.g.,
Mira, dynamic geometry software, compass) and strategies (e.g., paper folding)

If constructing perpendicular bisectors is the Aspirin, then how can we create the headache?  How can we create a situation where our students need to do lots of perpendicular bisectors?  Well, I wonder if creating voronoi could be a possible headache.  Take a look:

A Voronoi diagram is a partitioned plane where the area within each section includes all of the possible points closest to the original “seed” (the point within each section).  So, how might students create these?  If they already knew how to create perpendicular bisectors, they could simply start by placing seeds anywhere on their page, then create perpendicular bisectors between each set of points to find each partition.  However, Dan Meyer points out how important it really is to spend the time to really develop the skill starting from where our students currently are:

“In order for the CONSTRUCTION of the perpendicular bisector to feel like aspirin, I’d want students to feel the pain that comes from using intuition alone to construct the voronoi regions. This idea ties in other talks I’ve given about developing the question and creating full stack lessons. I’d want students to estimate the regions first.

Here is a dream I had awhile ago that I haven’t been able to build anywhere yet. Excited to maybe make it at Desmos some day.”

If you can, I’d recommend you take a look at Dan’s dream.  It really illustrates the idea of building his “full stack” lesson.  If we think back to the original standard again,

constructperpendicular bisectors, using a variety of tools (e.g.,
Mira, dynamic geometry software, compass) and strategies (e.g., paper folding)

it might be worth noting the specific pieces in orange.  I wonder, given a lesson like this, how much time would be spent allowing students opportunities to consider strategies that would make sense?  Or, how likely it would be that our students would be told which strategies/tools to use?

Below you can see the before and after images from a student’s work as they attempt to find perpendicular bisectors for each set of points.

Tasks like this do something else as well, they raise the level of cognitive demand.  Take a look at Stein et., al’s Mathematical Task Analysis Guide below:

While most students might experience a concept like this in a “procedures without connections” manner, allowing students to figure out how to create voronoi brings about the need to accurately find perpendicular bisectors, and consider how long each line would be in relation to all of the other perpendicular bisectors.  This is what Stein calls “Doing Mathematics”!  And hopefully, the students in our mathematics classes are actually “Doing Mathematics” regularly.

### As always, I want to leave you with a few reflective questions:

• How often are your students engaged in “Doing Mathematics” tasks?  Is this a focus for you and your students?
• If you were to ask your students to create voronoi, how much scaffolding would you offer?  If we provide too much scaffolding, would this task no longer be considered a “doing mathematics” task?  How would you introduce a task like this?
• Creating a perpendicular bisector is often seen as a quick simple skill that doesn’t connect much with other standards.  However, the task shared here asks students to make connections.  Can you think of standards like this one that might not connect to other standards nicely?  How can you build a need (or create the headache as Dan says) for that skill?
• Are you and your students “covering” standards, or are you constructing learning together?  What’s the difference here?

I’d love to continue the conversation.  Write a response, or send me a message on Twitter ( @markchubb3 ).

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## How Many Do You See (Part 2 of 2)

A few weeks ago I shared with you a quick blog post showing a simple worksheet at the grade 2 level – the kind of  simple worksheet that is common to many classrooms.  If you haven’t seen the image, here it is again:

As you can see, the task asks students to correctly count the number of each shape they notice.  In my first post (Part 1) I asked us a few questions to start a conversation:

1. Pick one shape (or more if you’re adventurous)
2. Think about what you believe the teacher’s edition would say
3. Count how many you see
4. Share the 3 points above as a comment here or on Twitter

I was quite happy with where some of the conversations led…

Some of the conversations revolved around the issue many have with resources perpetuating stereotypical definitions of shapes:

If we look, there are exactly 4 shapes that resemble the diagram at the top of the page labelled as “rectangle”, however, there are several different sized squares as well (a square are a special case of a rectangle).

Other conversations revolved around actually counting the number of each item:

What interests me here is that we, as a group of math teachers, have answered this grade 2 worksheet with various answers.  Which brings about 2 important conversations:

1. What are we looking for when students complete a worksheet or textbook questions?
2. Are we aiming for convergent or divergent thinking?  Which of these is more helpful for our students?

###### What are we looking for?

Given the conversations I have had with math teachers about the worksheet being shared here, it seems like there are a few different beliefs.  Some teachers believe the activity is aimed at helping students recognize traditional shapes and identify them on the page.  Other teachers believe that this activity could potentially lead to discussions about definitions of shapes (i.e., What is a rectangle?  What is a hexagon?…) if we listen to and notice our students’ thinking about each of the shapes, then bring students together to have rich discussions.

It’s probably worth noting that the Teacher’s Edition for this worksheet includes precise answers.  If a typical teacher were to collect the students’ work and begin marking the assignment using the “answers” from the teacher’s guide, some of the students would have the “correct” answer of 8 trapezoids, but many others would likely have noticed several of the other trapezoids on the page.  If we are looking / listening for students to find the correct answer, we are likely missing out on any opportunity to learn about our students, or offer any opportunity for our students to learn themselves!

I would hope that an activity like this would provide us opportunities for our students to show what they understand, and move beyond getting answers into the territory of developing mathematical reasoning.

###### Convergent vs Divergent Thinking

Again, many of the teachers I have discussed this activity with have shared their interest in finding the other possible versions of each shape.  However, what we would actually do with this activity seems to be quite different for each educator.  It seems like the decisions different teachers might be making here relate to their interest in students either having convergent thinking, or divergent thinking.  Let’s take a look at a few possible scenarios:

Teacher 1:

Before students start working on the activity, the teacher explains that their job is to find shapes that look exactly like the image in the picture at the top of the page.

Teacher 2:

Before students start working on the activity, the teacher tells the students exactly how many of each shape they found, then asks students to find them.

Teacher 3:

Before students start working on the activity, the teacher explains that their job is to find as many shapes as possible.  Then further explains that there might be ones that are not traditional looking.  Then, together with students, defines criteria for each shape they are about to look for.

Teacher 4:

Before students start working on the activity, the teacher explains that their job is to find as many shapes as possible.  As students are working, they challenge students to continue to think about other possibilities.

In the above scenarios, the teachers’ goals are quite different.  Teacher 1 expects their students to spend time looking at common versions of each shape, then spot them on the page.  Teacher 2’s aim is for students to be able to think deeper about what each shape really means, hoping that they are curious about where the rest of the shapes could possibly be leading their students to challenge themselves.  Teacher 3 believes that in order for students to be successful here, that they need to provide all of the potential pieces before their students get started.  Their goal in the end is for students to use the definitions they create together in the activity.  Finally, teacher 4’s goal is for students to access the mathematics before any terms or definitions are shared.  They believe that they can continue to push students to think by using effective questioning.  The development of reasoning is this teacher’s goal.

Looking back at these 4 teachers’ goals, I notice that 2 basic things differ:

1. How much scaffolding is provided; and
2. When scaffolding is provided

Teachers that provide lots of scaffolding prior to a problem typically aim for students to have convergent thinking.  They provide definitions and prompts, they model and tell, they hope that everyone will be able to get the same answers.

Teachers that withhold scaffolding and expect students to do more of the thinking along the way typically aim for divergent thinking.  That is, they hope that students will have different ideas in the hopes for students to share their thinking to create more thinking in others.

Whether you believe that convergent thinking or divergent thinking is best in math, I would really like you to consider how tasks that promote divergent thinking can actually help the group come to a consensus in the end.  If I were to provide this lesson to grade 2s, I would be aiming for students to be thinking as much as possible, to push students to continue to think outside-the-box as much as possible, then make sure that in my lesson close, that we ALL understood what makes a shape a shape.

#### I want to leave you with a few reflective questions:

• I provided you with a specific worksheet from a specific grade, however, I want you to now think about what you teach.  How much scaffolding do you provide?  Are you providing too much too soon?
• Do your lessons start off with convergent thinking or divergent thinking?  Why do you do this?  Is this because you believe it is best?
• How can you delay scaffolding and convergent thinking so that we are actually promoting our students to be actively thinking?  How can you make this a priority?
• What lesson or warm-ups or problems have you given that are examples of what we are talking about here?
• If we do remove some of the scaffolding will some of your students sit there not learning?  Is this a sign of them not understanding the math, or a sign of them used to being spoon-fed thinking?  What do WE need to get better at if we are to delay some of this scaffolding?

I encourage you to continue to think about what it means to help set up situations for your students to actively construct understanding:

I’d love to continue the conversation.  Write a response, or send me a message on Twitter ( @markchubb3 ).

P.S.  I’m still not confident how many of each shape are actually here!