Category: classroomaction

Total 39 Posts

A High School Math Teacher’s First Experience Teaching Elementary School

At a workshop in Alameda County last month, I made my standard request for classroom teachers to help me make good on my New Year’s resolution. I assumed all the teachers there taught middle- or high-school so I said yes to every teacher who invited me. Later, I’d find out that one of them taught fourth grade.

As a former high school math teacher, this was NIGHTMARE MATERIAL, Y’ALL.

I mean, what do fourth graders even look like? I’m tall, but do I need to worry about stepping on them? What do they know how to do? Do they speak in complete sentences at that age? Clearly, what I don’t know about little kids could fill libraries.

I survived class today. I used a Graham Fletcher 3-Act task because I’m familiar with that kind of curriculum and pedagogy. (Thanks for the concierge support, Graham.) A few observations about the experience, which, again, I survived:

Children are teenagers are adults. Don’t let me make too much of my one hour of primary education experience, but I was struck hard by the similarities between all the different ages I’ve taught. People of all ages like puzzles. They respond well to the techniques of storytelling. Unless they’re wildly misplaced, they come to your class with some informal understanding of your lesson. They appreciate it when you try to surface that understanding, revoice it, challenge it, and help them formalize it. I handled a nine year-old’s ideas about a jar of Skittles in exactly the same way as I handled a forty-nine year-old’s ideas about teaching middle schoolers.

Primary teachers have their pedagogy tight. Ben Spencer (my host teacher) and Sarah Kingston (an elementary math coach) were nice enough to debrief the lesson with me afterwards.

I asked them if I had left money on the table, if I had missed any opportunities to challenge and chase student thinking. They brought up an interesting debate from the end of class, a real Piagetian question about whether a different jar would change the number of Skittles. (It wouldn’t. The number of packages was fixed.) I had asked students to imagine another jar, but my hosts thought the debate demanded some manipulatives so we could test our conjectures. Nice!

Also, Spencer told me that when he asks students to talk with each other, he asks them to share out their partners’ thinking and not their own. That gives them an incentive to tune into what their partners are saying, rather than just waiting for their own turn to talk. Nice! As a secondary teacher, I felt like a champ if I asked students to talk at all. Spencer and his primary colleagues are onto some next-level conversational techniques.

Primary students have more stamina than I anticipated. No doubt much of this credit is due to the norms Mr. Spencer has set up around his “Problem Solving Fridays.” But I’ve frequently heard rules of thumb like “children can concentrate on one task for two to five minutes per year old.” These kids worked on one problem for the better part of an hour.

The pedagogy interests me more than the math.

This sentiment still holds for me after today. I just find algebra more interesting than two-digit multiplication. I’ll try to keep an open mind. Today was not an interesting day of math for me, though it was a very interesting day of learning how novices learn and talk about math.

I’m probably not wacky enough for this work. Mr. Spencer greeted his students by calling out “wopbabalubop!” to which they responded “balap bam boom!” Really fun, and I don’t think you can teach that kind of vibe.

Loads of algorithms, and none of them “standard.” Graham’s 3-Act modeling task asks students to multiply two-digit numbers. I saw an area model. I saw partial products. Students used those approaches flexibly and efficiently. They were able to locate each number in the world when asked. I didn’t see anyone carry a one. Everyone should settle down. This is great.

I expected the experience would either kill me or convince me I should have taught primary students. This one fell somewhere in the middle. I’m excited to return someday, and I was happy to witness the portability of big ideas about students, learning, and mathematics from adult education to high school to elementary school.

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Marilyn Burns:

I remember my first venture in elementary school after teaching ninth grade algebra and eighth grade math for four years. I was curious about younger students and my friend invited me into her third grade class. I can’t remember anything about the lesson I taught, but what I do remember is that I made a student cry. He had done something that I thought was inappropriate behavior and I must have responded pretty harshly. Hey, I was used to teaching older tough kids and I had never thought about modulating my response. It wasn’t my finest hour and I was devastated. My friend helped me through the experience and I even went back. After then I learned other ways to talk with younger students and became more and more fascinated about how they formed their conceptions . . . and misconceptions . . . about mathematical ideas. I’m hooked.

You Can’t Break Math

We were solving linear equations in Ms. Warburton’s eighth grade class last week and I learned (or re-learned, or learned at greater depth) a couple of truths about mathematics.

As I approached B and R, I misread them as disengaged. In fact, they were thinking really, really hard about this beast:

B suggested they multiply by two as a “fraction buster.”

(One small pleasure of guest teaching is trying to identify and decode the vernacular of each new class. I heard “fraction buster” more than once.)

R asked, “But do we multiply this by two or the whole thing by two?”

If you’ve taught math for a single day, you know the choice here.

You can tell them, “You multiply the whole thing by two.” That’d be helpful by the definition of “helpful” that includes “completing as many math problems as correctly and quickly as possible.” But in terms of classroom management, I’ll be doing myself no favors, having trained B and R to call me over whenever they have any similar questions. More importantly, I’ll have done their relationship with mathematics no favors either, having trained them to think of math as something that can’t be made sense of without an adult around.

Variables like x and y behave just like numbers like -2 and 3.” I said. I wrote this down and said, “Try out both of your ideas on this version and see what happens.”

After some quick arithmetic, they experienced a moment of clarity.

In the next class, students were helping me solve 2x – 14 = 4 – 2x at the board. M told me to add 2x to both sides. One advantage of my recent sabbatical from classroom teaching is that I am more empathetic towards students who don’t understand what we’re doing here and who think adding 2x to both sides is some kind of magical incantation that only weird or privileged kids understand.

So at the board I was asking myself, “Why are we adding 2x to both sides? What if we added a different thing?”

Then I asked the students, “What would happen if we added 5x to both sides? What would break?”

Nothing. We decided that nothing would break if we added 5x to both sides. It wouldn’t be as helpful as adding 2x, but math isn’t fragile. You can’t break math.


  • I haven’t found a way to generate these kinds of insights about math without surrounding myself with people learning math for the first time.
  • One of my most enduring shortcomings as a teacher is how much I plan and revise those plans, even if the lesson I have on file will suffice. I’ll chase a scintilla of an improvement for hours, which was never sustainable. I spent most of the previous day prepping this Desmos activity. We used 10% of it.
  • Language from the day that I’m still pondering: “We cancel the 2x’s because we want to get x by itself.” I’m trying to decide if those italicized expressions contribute to a student’s understanding of large ideas about mathematics or of small ideas about solving a particular kind of equation.

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Here is an awesome sequence of comments in which people savage the term “cancel,” then temper themselves a bit, and then realize that their replacement terms are similarly limited:

Corey Andreasen:

I have a huge problem with ‘cancel.’ It’s mathematical slang, and I’m OK with its use among people who really understand the mathematics. But among learners it obscures the mathematics and leads to things like “cancelling terms” in rational expressions.

Melissa Lechleiter:

I think the word “cancel” is misused in math when teaching students. We are not canceling anything we are making ones and zeros.


I never say cancel. I’ve worked hard to eliminate it from any teaching I do. Same with cross multiply, never say it. Instead I say “add to make zero” or “divide by or multiply by the reciprocal of to make one”.

Sam Shah:

We use “cancel” to mean too many things and so they use the term anytime they want to get rid of something or slash something out. The basis for my concern: when I ask kids “why can you do that?” they often can’t explain.

Jeremy Hansuvadha:

However, when it comes to squaring a square root, what is most accurate to say? I don’t correct the kids in that case, and I tell them that cancel means the same thing as “undo”.

Paul Hartzer:

If the point is to be rigorous, “apply the inverse” is more rigorous and technical than “cancel”.

More miscellaneous wisdom on language in mathematics:

David Butler:

In the topic of “get x by itself”, I’ve started saying “We want to say what x is. What would that look like?” They usually say “It would look like x = something”. Then they’ve chosen what the final equation ought to look like for themselves.

I wonder what would happen if we had an equation and then asked them to find out what, say, 2x+1 was.

Joel Penne:

Even in my Advanced Algebra 2 classes I have started using the phrases “legal” and “useful”. In the original post adding 5x to both sides was definitely “legal” just not as “useful”.

Laura Hawkins:

One of my refrains is that an algebraic step is “correct, but not useful.” Inspired by my dance teacher, I also talk about how a particular procedure is lovely, just not in today’s choreography (which is geared towards solving for an unknown/simplifying a trig expression/ finding intercepts, etc).

Great Classroom Action

Tracy Zager illustrates a key feature of some of my favorite math tasks: their constraints are simple, but they create paths for complex thinking and ever more interesting questions:

I think my name is worth $239. Beat me? Haven’t figured out my $100 strategy yet.

Lisa Bejarano is a recipient of our nation’s highest honor for math teachers, so when she admits “I have no idea what I am doing” and starts sketching out a blueprint for great classrooms, I tune in:

Now, beginning with the first day of school, I intentionally work at building a unique relationship with each student. I make sure to find reasons to genuinely value each of them. This starts with weekly “How is it going?” type questions on their warm up sheets and continues by using their mistakes on “Find the flub Friday” and through feedback quizzes. I also share a lot of myself with them. When we understand each other, my classes are more productive. I still make plans, but I allow flexibility to meet my students where they are.

David Cox describes “a difficult thing for students to believe”:

Once students begin to believe that the way they see something is the currency, then our job is to simply help them refine their communication so their audience can understand them. Only then does the syntax of mathematics matter.

“Help me understand you.”

“Help me see what you see.”

Kevin Hall thoughtfully deconstructs his attempts to teach linear function for meaning, and includes this gem:

Once you introduce the slope formula, slope becomes that formula. It barely even matters if today’s lesson created a nice footpath in students’ brains between “slope” and the change in one quantity per unit of change in another. Once that formula comes out, your measly footpath is no competition for the 8-lane highway that’s opened up between “slope” and (y2–y1)/(x2­-x1).

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Great Classroom Action


Tricia Poulin makes some awesome moves in her #bottleflipping lesson, including this one:

Okay, so now the kicker: will this ratio be maintained no matter the size of the bottle?

Graham Fletcher offers us video of kindergarten students interacting in a 3-Act modeling task:

It’s always great to engage the youngins’ in 3-Act Tasks. I’ve heard colleagues say, “I don’t have time to do these types of lessons.” I hope this helps show that we don’t have time to not have the time.

Wendy Menard offers her own spin on the Money Duck, one of my favorite examples of expected value in the wild:

The students designed their own “Money Animals”, complete with a price, distribution, and an expected value. This was all done on one sheet; the design, price and distribution were visible to all, while the calculations were on the back. After everyone had finished, we had our Money Animal Bonanza.

Sarah Carter hosts the Mini-Metric Olympics, a series of data collection & analysis events with names like “Left-Handed Sponge Squeeze” and “Paper Plate Discus”:

After the measurements were all taken, we calculated our error for each event. One student insisted that she would do better if we calculated percent error instead, so we did that too to check and see if she was right. In the future, I think I would add a “percent error” column to the score tracking sheet.

Great Classroom Action


A. O. Fradkin used her students as manipulatives in a game of addends:

The classic mistake was for kids to forget to count themselves. Then I would ask them, “How many kids are not hiding under the blanket?” When they would say the number of kids they saw, I’d follow up with, “So you’re hiding under the blanket?” And then they’d laugh.

Cathy Yenca put students to work once they finished their Desmos card sorts:

From here, it becomes a beautiful blur. Students continue to earn “expert” status and become “up for hire”, popping out of their seats to help a bud. At one point today, every struggling student had a proud one-on-one expert tutor, and I just stood there, scrolling through the teacher dashboard, with a silly grin on my face.

I’d love to know how we could employ experts without exacerbating status anxieties. Ideas?

Laurie Hailer offers a useful indicator of successful group work:

It looks like the past six weeks of having students sit in groups and emphasizing that they work together is possibly paying off. Today, instead of hearing, “I have a question,” I heard, “We have a question.”

David Sladkey switches from asking for questions to requiring questions:

My students were working independently on a few problem when I set the ground rules. I told my students that I was going to require them to ask a question when I was walking around to each person. I also said that if they did not have a math question, they could ask any other (appropriate) question that they liked. One way or another, they would have to ask me a question. It was amazing.

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I also have kids sign up to be an expert during group work, indicating that they’re open to taking questions from other students. Sometimes, after a really good small group conference, I’ll ask a student to sign up to be an expert.