College Algebra: Quadratics

 I had my elementary ed class canceled for low enrollment this fall. Make of that what you will.

The replacement course is College Algebra. Ironically named, since it is mostly Algebra 2. Which is required in Michigan. Our sequence has been 097 (prealgebra) -> 110 intermediate algebra (algebra 1) -> 122 College Algebra.  It used to be + 123 (trigonometry) to go on to Calculus, but we have a nice precalc class now (124) so people needing to take calculus that don't place into it can just take 1 semester. The audience for 122 then, is now general education, and people who need courses that require it, like the basic chemistry, intro physics, and statistics. It's a 3 credit course, and my section meets twice a week.

The course has traditionally been quadratics -> polynomials -> rational functions -> exponentials -> logarithms -> light touch of statistics. So what do we want from the quadratics unit? This post is me trying to think out loud to get it straight for myself. The schedule is pretty packed, so I have 2-3 weeks per topic, 4-6 class periods.

The instructional sequence I have planned is visual patterns -> modeling (Penny Circle and Will It Hit the Hoop?) -> graphing/equation forms (Match My Parabola & Form Fix) -> solving equations (vertex form & graphing), mostly in a modeling context.

The visual patterns do a lot of work. They offer a hook, they give learners a chance to notice and wonder, they give us a chance to problem solve. They are also different from what most students have seen in algebra, sadly, so offer a way to let them know that this course might be different. I also have them read Elizabeth Statmore's post on math as a thinking class. I asked them, "What do you think the main idea is? How does this compare with your own ideas about learning math or your previous experiences?" and you can read their responses on this doc.  I think they get it. Mathematically, I think my main point is the use of variable as a relationship rather than an unknown. The transition from step number to x is very natural. Secondarily, they get to see multiple equivalent expressions. Which is one of those math ideas which many learners see as a bug, but mathematicians think is a central feature.  Part of the richness of these problems is what the old NCTM standards called the representation process standard. Tables, expressions, visual and the connections between them all move us forward. Here's a handout with four quadratic patterns. The bricks and the darts and kites are very difficult to visual make a symbolic rule for. I might have made them or might have found them at Fawn Nguyen's visualpatterns.org or it could be a mix.

Modeling is a key theme of the course, and Penny Circle and Will It the Hoop? are a good start to it. I was surprised how many learners went with an exponential form, and the reveal is the perfect way to settle it. We will be using Desmos activities a lot, and those are pretty slick introductions. The Penny Circle builds on the covariation use of variables, and the basketball leads into the graphing we'll be working on next. 

This is where we are as I write.

I'm convinced that one of the barriers for these students is understanding graphs. Thankfully, making them is easier than ever. But I don't think that many know how to think with them. Again with the representation standard, the connections between the symbolic expression and the graph is mostly taxonomical, and I want it to have meaning. Though this is a place where I could use some help. Regression supports this goal, as it brings tables into the web of connections. Activities where they vary parameteers and observe the effect on the graph help, at least in terms of taxonomy. Solving equations with graphs is an opportunity to build some of the understanding I want, as, especially for applications, the context is another piece of the representation. Writing this, I'm a little surprised by how hard it is for me to put my goal here into words. That would undoubtedly help with the teaching!

Solving equations is last for me, partly because it is so much what they perceived the focus to be in their previous math courses. I don't care especially for a lot of symbolic skill here. I don't teach solving by factoring, though the factored form in connection with graphs is something I emphasize. I do like the approach of solving from quadratic form, because it builds on a theme in math I love about doing and undoing. This leads better into exponentials and logarithms than it does polynomials and rational functions. The symbolic fluency that I want is being able to see a quadratic as series of steps. Take a number, subtract 2, square it, double it, add five is the same as  . To find what numbers make 13 from that function, we can do by undoing.  I love Graspable Math for this, as the dragging to undo seems to really help get across the idea, though it doesn't work on the balance nature of equations. Here's an example GM activity with 3 quadratics to solve.

I'm very interested in your thoughts. What are the key ideas you want in a quadratics unit? What am I leaving out that you love? What understanding do you want your learners to develop or skills do you want them to have for graphing? Why?

P.S.

Probably violating some internet rule here, but really liking the Twitter discussion about this post.

@DavidKButlerUoA: This line was very interesting: "multiple equivalent expressions... is one of those math ideas which many learners see as a bug, but mathematicians think is a central feature". I'd love to hear more about that.

@joshuazucker: My interpretation is that beginners may want there to be only one answer and experts see how useful it is to have multiple representations that make different behaviors immediately visible.

@mathcurmudgeon: When 90% of calculus (and every math course, really) is rewriting expressions in an equivalent form that we can work with more easily.

@mathhombre: it starts with fractions. All these different ways to write the same thing. One of them must be right. (Often supported by teachers insisting on one.)  But that we can transform, rewrite and tinker leads to fluency, connections, and meaning.

@mathforge: The belief that out of all the ways of writing it there must be a RIGHT way is SUCH an interesting belief. I've never thought before that people might believe this.

I suspect that this is more prevelant than we might admit. As experienced mathematicians we might chuckle at people who think that there is a "best" way to write, say, a quadratic or a fraction. But we probably fall into the same trap with ideas.

I might, to take a random example, think that there is a "right" way to think about differentiation, or Pythagoras theorem, or a topology, or the category of smooth functions. What I mean is, "this is the way I find most intuitive".

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@KarenCampe: Love the visual patterns start & modeling focus. 

When you do graphing equation forms & use match my graph/form fix you will surely cover symmetry of the graphs & how factoring gives x-ints. I like how graphing & alg manipulation of quadratics are interconnected...

Use graphing as tool to support any algebraic rearranging we might want. Look for hidden parabola that shows complex roots. Axis of symm hidden in quadratic formula.

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[In response to "Quadratics unit in a college algebra course. What goes in, what's left out? "]

@theresawills: Probably too vague, but worth saying: RICH PROBLEM SOLVING.

 

ꓕWCƖ8

My favorite professional meet of the year has come and gone. Here's what I'm still thinking about... divided into everything else and the equity session, Take a Knee, led by Marian Dingle and Wendy Menard.

Necessary proviso: there is so much good at a TMC.  The signal to noise ratio is unimaginable compared to any other meeting/conference I've been to. I'm not trying to represent everything, and I'm skipping good stuff. This is literally what I'm still thinking about.

Everything Else

Desmos preconference: this was all about computation layer for me. Despite Michael Felton's great introduction last year I did nothing with it. Sigh. Now I feel like maybe I could, if I get some time to just process. There's a help forum, an improved Scavenger Hunt (which are the learning activities) and some documentation. Look at Chase's and Madison's Estimation Stations for what is possible. (Or watch their My Favorite on it)Plus Eli's description that computation layer is really about connecting pipes to send data. Connect a source to a sink. Christopher led a design session that covered their principles for building an activity and showed it in action in the activity Marcellus the Giant. That was also the first peek of Snapshot, an amazing new teacher tool. Turn any of the Desmos tools on or off at teacher.desmos.com/labs.

Marian's keynote. Quiet, intense and personal. This is directly a challenge to the community of math teachers. Are we on the side of equity? Are we doing what we can? Do we even see the problems, issues and concerns in front of us. Please watch.

Amie Albrecht teaches a problem solving course where she is doing so much fabulous pedagogy. The course has explicit goals of learning to problem solve, and to be able to share that verbally/presented or in writing. Feedback before grading, reiteration with wider and wider audiences... just beautiful. Folder of resources. Some things I'm still thinking about for our teacher education classes and for the redeeming mathematics class. Part of it, the Back of Mathematics, she shared as a My Favorite.

I caught Robert Berry's keynote at Desmos and his afternoon session on day 1 on the NCTM's Catalyzing Change book. Honestly, because I am terrible at reading programs ahead of time, I was just surprised he stayed! He really participated and was great about connections between the MTBoS and NCTM. One of the cool things in Catalyzing Change is that the NCTM is against tracking of students and of teachers. Are the most effective teachers teaching all the students? I do think it is a huge mistake for NCTM to paywall their essential high school content in this book. The 1999 Standards and Principles were so formative for me, and so hard to get into teachers hands. One lesson I'd love for NCTM to get from the teacher twitter community is that shared resources increases buy-in and participation. Teachers are naturally community-minded, and if you make them welcome and support them they will join. (Opinion.)

Julie's keynote. I was in two minds here. One, appreciative audience in need of the message, and two, person speaking the next day having to follow Marian and this. Wurg. The impostor syndrome message was timely. And if an old man who speaks regularly and has taught for 30+ years feels that way... sigh. But also, as a teacher educator, her message about being a teacher leader was perfect. It's not about doing everything, it's about finding what you love, doing that, and sharing. It reminded me of Dave Coffey's favorite Teaching Gap quotation:

The star teachers of the twenty-first century will be teachers who work every day to improve teaching—not only their own but that of the whole profession. -Stiegler & Hiebert

Sasha Fradkin presented on impossible problems. I love the idea of learners doing the work of mathematicians, and showing something can not happen is just as important as finding out what can. But how rarely do we ask them to do that? I'm still tossing over in my head what the difference might be between doing a general investigation, and specifically asking for outcomes that can't happen. Sasha is the author of Funville Adventures, which session I missed, but be sure to check it out.

Brian Bushart is still developing numberless problems with the teachers and learners of Red Rock.  It's really impressive to me, that they are making some great improvements to something that was already fabulous. But he realized that some teachers were using the structure in a deficit mindset. And thinking about Rochelle Gutierrez's ideas about mathematics identity, they reframed the problems with a story telling lens. Just amazing. (His slides.)

Some My Favorites: (all the TMC18 vids from Glenn Waddell)

• Annie Perkins Phone Calls
• Megan Schmidt Elementary Love Letter
• Kent Haines Games for Young Minds (gamesforyoungminds.com )
• Sam Shah Math Flavors Festival (Festival posts)
• Chris Nho Problem Solving
• Justin Aion Classroom Discourse Philosophy

Take a Knee
I spend a lot of time thinking about this, and trying to educate myself. I try to use the understanding I build as an inclusion advocate at the university, and in my teacher education classes, as well as some local work in the community. Despite all the time I spend reading about this, I am constantly humbled by how much more there is to learn and work to do on my own thinking. Last year's TMC session by Grace Chen, Brette Garner, and Sammie Marshall revolved around connections between equity and the Standards for Mathematical Practice. Personal work included developing a checklist to get past our internalized schema, and 'equity eyes' -training ourselves to see. (All three are/were Lani Horn's grad students. Never wrote it up for the blog, bad blogger.) It revolved around developing equity eyes.  This year I got to see Calvin Terrell who sometimes refers to this work as decolonizing. Then a 5 week workshop at work was titled Decolonizing White Consciousness, which seemed timely. That featured work of Robin DiAngelo (watch this on white privilege), adrienne maree brown (read Emergent Strategy), and a variety of readings and videos around the idea of identity.

So the morning sessions for me came down to Take a Knee or Islamic Art, and I couldn't not join Wendy and Marian. (Session resources. Twitter - #tmcequity) Both were a part of the TMC17 equity session and Wendy & José Luis Vilson's Racially Relevant Pedagogy session at TMC16 is the single most affecting hour workshop I've ever been to.

Day 1 started with us introducing ourselves with our identities. This feels very odd if you're part of a group or groups that gets to take this for granted. Straight, more white than not, male... naming has power and self-naming invites vulnerability. The day closed with an activity for trying to suss out how central all these identities are to you. It was gently brutal. In between, we tried to figure out what take a knee even meant in the context of our work in math education. A theme that continued over the three days started here: equity for our students and what did that mean, and using our lessons as a way to be relevant and real with our learners. Both are a part of the larger discussion of how teaching is political.

Day 2 revolved around standards and methodologies. Teaching Tolerance's Common Beliefs help us understand how what teachers bring to the classroom influences what we teach, and the Standards for Social Justice are as good a framework as I've seen for how we should aspire to teach. Rochelle Gutierrez's article on Creative Insubordination (in here from TODOS) provided a lot to talk about. And we had an awesome poster session on that.

It's insubordination because we are consciously trying to work against the status quo.

Day 3 was preparing to go back into our worlds. We began with powerful identity statements again. "Because of my race I can..." Says something about a group of people that can share such things. We then worked in small groups on what we can do, short, medium and long range.  My group was thinking about math lessons that reflect and think about the diversity of our schools, communities and country.

For me:

• Short: diversify follows on Twitter. I got some great suggestions in responses to this tweet, and from the hashtag #disrupttexts.
• Medium: incorporate SJ standards into teacher training.
• Long: transform colleagues. Makes me woogly just to say it.

Further reading: Kent Haines - Pedagogy and Equity, Dylan Kane - Disrupt Math, Michael Pershan (not even there!) - Power Works by Isolating.

Next Year

Still thinking about this. I've been lucky enough to go 5 years in a row - is it time to make space for someone else? Selfishly, it is amazing to participate. But there won't be space if all the same people always go. I'm also conscious of not being a classroom teacher, and the thought of taking that spot is chilling. Maybe the TMC Midwest will happen? And absolutely no judgment on anyone else who is a repeat attender - I am only trying to process this for myself. 

Super Mathio

Hedge wrote this fun post on Mario Brothers and math - specifically parabolas - that got me to tweet: I also now want a video game where you jump by clicking the vertex to make a precise parabola based on where you are. She asked the good question: Can you make that?

Should have thought that one through.

Fortunately, though, it's Twitter, so brilliant people to the rescue.

Desmos tweeted:

 

Pretty sweet! Find it at Desmos:

Beyond my current Desmos levels, but pretty amazing. Great image use. 

Then Andrew Knauft tweeted:

Find it at OpenProcessing.

You click to do the jump. Beyond my current Processing skills, but excellent.

So I did -of course- have to try it in GeoGebra. I'm pretty happy with the result. The math wasn't too hard, though the scripting the buttons and resetting graphics is always tricky for me.

It's at GeoGebraTube for you to play with. There's a data mode that let's you try to calculate the best high point first - which is where I would want to go with it. It's an insufficient data situation as I purposely left off the coordinates of the bonus box.

There are some things to notice about parabolas as you play it, and for deeper work it would be interesting to think about how to add scoring.

GeoGebra Note: Andrew Knauft also helped with this! You define piecewise functions in GeoGebra using the If command, which also has an else variant. I.e. either If[<condition>,<then>] or If[<condition>,<then>,<else>]. I was getting errors with the inequalities to make the towers, and Andrew figured out that GGB didn't like an inequality with the else form. Redefined them as Ifs alone, and I was good to go.

This was very fun. I'm curious to know if or how you would use it, or what features you might add. As always, if you have an idea for dynamicizing, let me know!