Sunday, February 9, 2014

Dear Class,

It seems to me that you are suffering from a mid-year slump – maybe having to do with some disappointment about the recent midterm exam, or maybe something more. Recently I have heard: “You never taught us that.” “Nobody cares about understanding. Only the grade matters.” “I haven’t learned anything in here.” “You don’t like me.” And a few more. Ouch.

You may fault me for not being a teacher who leads you through every step of the way. It’s true. I ask you to practice problems on the homework that are harder than what we did in class. I ask you to be ready for a graded assessment at any time, and without warning. I ask you to be assertive and self-aware - requesting clarification when you need it, both inside and outside of class. I also put problems on tests that I have not previously solved for you in class. I know this makes it more challenging, but to me it’s the best way. I see the world of mathematics as a vast universe of possibility. I get to be your guide for only this tiny little region, but ultimately, I want you to trust your own instincts and skills and venture out without me.

You have a choice to make. One option is to be bold; take a leap out into the vastness and use the tools you already have to find your way through this wonderful world. I promise: you are not alone; you will not perish; and when you find that you need new tools, they will be there, ready for you to learn how to use them. Or, you can sit still and wait for a personal guide. It’s ok; sometimes this is the better way. I know that fear or insecurity or any number of things can freeze any of us in our tracks. Nevertheless, I cannot stop encouraging you to be bold and venture out independently, because I know that a richer and more beneficial world is there for those who do.  There will always be problems on ‘tests’ that have not been previously modeled for you. This much, I can guarantee. I wish we lived in a world where all the problems were previously solved, but I assure you, you will be confronted with problems that I cannot even imagine yet. The question is, what will you do with those?

In the end, it’s not important to me whether you attribute your growth to me or not. I just hope you notice what I do: that you HAVE grown. Don’t let the vastness of the universe lead you to a narrow view of your own successes. You have come a long way. I have evidence to prove it. And while we both know that there’s an even wider view in front of you, that doesn't diminish the excellent work you have done to get this far. It is one of life's great ironies that success and failure travel so well together:
“Failure is simply the opportunity to begin again, this time more intelligently.” Henry Ford
“I know that I am intelligent, because I know that I know nothing.” Socrates
“It’s not that I’m so smart, it’s just that I stay with problems longer.” Albert Einstein 
I've missed more than 9000 shots in my career. I've lost almost 300 games. 26 times, I've been trusted to take the game winning shot and missed. I've failed over and over and over again in my life. And that is why I succeed. Michael Jordan


Saturday, September 22, 2012

6 Essential Questions in Algebra

A year ago, I began this blog with the goal of uncovering some satisfying essential questions in algebra. These were to be questions that addressed the fundamental essence of algebra, while also being able to extend beyond a single discipline... and of course, they needed to be intriguing to both my students and to myself. A few months later I wrote that one of the qualities of a REALLY good math teacher is having a 'second set of objectives that go beyond the mastery of today's content.' A reader challenged me to identify these objectives, which I slyly avoided. But this week, in honor of my one year blogoversary, I present six essential questions or 'higher objectives' for my algebra classes. It's a start. In the spirit of UbD, expositions are voiced in the language of enduring understandings.

How is algebraic thinking different from arithmetic thinking?


It is my hope that my students will understand that algebra is a language of abstraction, where patterns are generalized and symbols are used to represent unknown or variable quantities. Arithmetic involves counting and manipulation of quantities where algebra relies more heavily on reasoning and generalizing the patterns that are observed from arithmetic procedures. It is my ultimate hope that they come to appreciate the power and utility of generalization.

What makes one solution better than another?


I would like my students to understand that numerical accuracy is only one piece of a good solution. The measure of a comprehensive and satisfying solution involves a subtle balance of precision, clarity, thoroughness, efficiency, reproducibility, and elegance (yes, elegance). I want my students to be masters of the well-crafted solution.

How do I know when a result is reasonable?


I want my students to understand that in math, as in life, context is supreme. There is no 'reasonable' or 'unreasonable' without an understanding of context. I hope that they can refine the skills to analyze and dissect problems that are both concrete and abstract, applied and generalized. I want them to develop habits of inquiry, estimation, and refinement. Ultimately, I hope that they will improve their sense of wisdom.

Do I really have to memorize all these rules and definitions?


Students will understand that mathematics is a language of precision. Without explicit foundations (axioms and properties) and precise definitions, reason gives way to chaos. On the other hand, they should understand that many perceived 'rules' in mathematics are simply shorthand ways to recall a train of logical reasoning (like formulas and theorems). It is my hope that they will appreciate precision but also understand the value of reason over recall.

Isn't there an easier way?


Without destroying their fragile spirits, I want my students to appreciate the benefits of struggle. I want them to realize that insight and higher knowledge are gained by approaching a problem from different angles and with multiple methods and representations. I want them to understand that knowledge about how mathematics works is on a higher echelon than the solution to a particular problem. In my ideal classroom, the students will understand how to spark their inner intrigue in order to move themselves beyond answers to seek connections, generalizations, and justifications.

Do I really need to know this stuff?


By sheer repetition and example, my students will know that the practical applications of algebraic thinking are numerous, especially in the rapidly changing fields of science, engineering, and technology. Beyond these undeniably important applications, they will know that confirmed correlations have been made between success in algebra and improved socioeconomic status. But ultimately, I hope that they will understand that the beauty and intrigue of mathematics is vast, and the limit of its power to improve the quality of their lives is unknown. I want them to glimpse infinity.

Sunday, September 9, 2012

What's the Big Idea with Algebra 2?

Lately, I've been following some of the conversation around the big ideas in an advanced algebra/pre-calculus course. The Global Math Department* hosted an interesting panel discussion around this topic a couple of weeks ago. I appreciated the thoughtfulness and complementary ideas of the presenters (John BurkDan Goldner, Michael Pershan, and Paul Salomon), and especially the thoughts behind proof and 'the well-crafted solution.' Without entirely reaching a consensus, the focus of the discussions tended to lean towards prediction as the overarching theme for algebra ii. The reasoning was thoughtful and grounded, but this theme did not satisfy me. While I can certainly see it, I also think that prediction is the theme for statistics. Can Algebra 2 and Statistics have the same theme? They can, I suppose, but it is not satisfying enough.

Some of the new bloggers from the New Blogger Initiative also tackled this topic last week.
gooberspeaks got me thinking about the focus on families of functions and David Price included ideas about varying ways of representing functions and modifying their behavior. Kyle Eck has a strong bent towards applications which resonates with the GMD theme of predictions. And all these ideas muddled around in my brain for a long time before emerging as a single construct that currently satiates my desire for deeper inspection.

Algebra 2 is all about: generalizing patterns of behavior in bivariate relationships.

But that's my academic's definition. In the UbD-influenced language of a high school classroom, I'd say that Algebra 2 asks these questions:

  • How can we communicate the behavior of a relationship between two ideas?
  • Are there rules of behavior that apply to all relationships?
  • Why is it important to be able to generalize patterns of behavior?

Functions certainly play a large role here, because it's easier to generalize patterns when there are overt rules of behavior to follow. But just as importantly, we also look at conic sections and the elusive inverses of even polynomials and periodic functions, because these ideas give us essential insight about the comforting nature of functions that are both one-to-one and onto, and about the obstacles presented by relationships that are not.

Graphing also plays a large role, because it is a most excellent tool for alternate representations of bivariate relationships. Seeing patterns emerge in the shape of coordinate graphs can be enlightening long before symbolic manipulation clears a path through the brain... and I thank the math gods for that! I am wary though of too much graphical emphasis, for our well-loved coordinate system has obvious limits as our brains allow us to consider relationships with more variables.

And applications clearly play an important role too, especially in the attempt to answer that third question. But I hesitate to put applications at the forefront of an advanced algebra theme. I think that is perhaps better handled by a physics class. In algebra we are attempting to represent scenarios with a generalized pattern of behavior, and manipulate this generalization to highlight useful information. I think I agree with Paul Salomon in that proof and 'well-crafted solutions' may trump (but certainly not replace) applications in the hierarchy of an overarching theme in algebra.

To end, I'll just say that my desire to ask (and attempt to answer) the big questions is never entirely satiated, but I do so enjoy the conversations that emerge from them. I welcome your thoughts, criticisms, and further insights. The discourse is what makes being a mathematician so much fun.

*Megan Hayes-Golding, where have you been all my life? What a terrific thing the GMD is, and one of these Tuesday nights, I will not have bedtime routines or NBI deadlines to worry about and will be able to attend a session while it is actually happening! Thanks to you and all others who are making this happen.

Tuesday, September 4, 2012

Parenthetically Speaking

I imagine that you, like me, have taught, or retaught, or referred to parentheses in the traditional manner:
Parentheses are used in mathematical expressions to denote modifications to normal order of operations (precedence rules). In an expression like (3+5)×7, the part of the expression within the parentheses, (3+5)=8, is evaluated first, and then this result is used in the rest of the expression. Nested parentheses work similarly, since parts of expressions within parentheses are also considered expressions. Parentheses are also used in this manner to clarify order of operations in confusing or abnormally large expressions. (from Wolfram Math World)
Wolfram goes on to define seven other mathematical uses for parentheses, including interval notation[0,5), ordered pairs (0, 5), binomial coefficients (n; k), set definitions (a,b,c), function notation f(x), etc. With so many uses, it's perhaps no minor miracle when students are able to emerge with any working facility of parentheses at all!

Honestly, I feel for my students. Even to me, mathematical definitions can sometimes seem inconsistent and confusing. Like the difference between terms (things that are added) and factors (things that are multiplied).
 I can hardly keep my own head on straight to describe the number of terms (2) and factors (0) in the following expression:

(To be fair, the first term consists of two factors, each containing two terms each, and the second term has four factors.)


And then recently, I reviewed a prealgebra curriculum that described parentheses as symbols that tell us to "treat part of the expression as one quantity." (from onRamp to Algebra) The book goes on to further implore the teacher to forgo the order of operations description in lieu of the 'one quantity' idea.

I knew that... 


So WHY have I NEVER thought to describe it that way??? 

Parentheses are grouping symbols that tell us to treat the group as a single entity. Period. No confusion. 

A function input is a single argument.
An ordered pair is a single location.
An interval is a single, uninterrupted region.
A matrix is a single array.
A set is a single collection.
A binomial coefficient is a single combination.
An expression in parentheses is a single quantity.

For some reason, this simple statement of an idea that seems so obvious is completely enlightening to me. The Common Core lists "Look for and make use of structure," as one of its Standards for Mathematical Practice. To me, this 'single entity' idea is paramount to the mastery of this standard: the key to seeing structure in long complicated algebraic expressions.

I find a subtle beauty in tiny moments of enlightenment, even if it is only my own. It's got to rub off on someone!

Sunday, August 26, 2012

Reflections and Transformations

In my town, school starts this week. My children have new backpacks and lunchboxes and shiny pencil cases with 5 newly sharpened pencils in each. The New Blogger Initiative is filled with stories of first day jitters and school year goals. This is a hard time for me.

Ask me what I do, and I'll tell you that I am a math teacher. I have taught in urban, rural, and suburban schools. Unfortunately, life handed me a pink slip last year. It happens. Budgets get cut and new jobs are not stable jobs. But even without a classroom, I am still a math teacher. You are what you are. At the risk of sounding vainglorious, I know I am a good teacher. Not REALLY good, but working towards it.

So this past year I took the pink slip as an opportunity to reflect, learn, write, grow, and move into a new era. I started this blog (and thank the Initiative for kicking my butt into keeping it up). I took a very close and critical look at lots of stuff in my filing cabinet. I have made a little money by offering some of these things for sale. I know the mathtwitterblogosphere is a sharing culture. I have lots to share, but I have mixed emotions about sharing everything. So I may not be as avuncular as Sam Shah, but I hope to create a helpful space here on my blog.

Here's my first day syllabus. I've used it for a lot of years and it probably needs an update, but I still like it.
syllabus

I use this same format for all my classes, with tweaks to supply lists and calculator guidelines etc. The editable Word file is here, although it doesn't translate very well in Word (I use Publisher mostly, but no one else seems to). You'll have fun making it your own. I do.

Now, before you start feeling sorry for me and sending me job listings, I'm being picky. I know what it's like to be me as a teacher. It's a 50+ hour/week commitment, with lots of worry and stress. I'm at a stage in my life where I don't wish to handle too many other external stressors. 10 minutes is about my limit on commuting time. Besides the extra time, I just like teaching close to home, in my own community, where I run into kids on the street and their parents at the grocery store. Some people don't want this, but I do.

So in the meantime, I have a job. I edit math curricula at a huge publishing operation. I spend lots of time thinking intensely about tiny details, which is a wonderful contrast to teaching - where you have teeny amounts of time to maneuver a plethora of calamities. In the past several months I have been able to deepen my appreciation for:

  • The pervasive misunderstanding of the difference between the terms inverse and opposite.
  • The devastating impact of intermediate rounding.
  • The art of posing just the right question to provoke intrigue and deepen student understanding.
  • The subtle mathematical properties of okra.

Okay, maybe not that last one, but the point is that even without actually being in the classroom, I still find myself improving as a teacher. I see that there is a long and fascinating road both before and behind me. There are things to share and things to learn. Luckily, the company continues to be great, and just keeps getting better. Thanks for YOUR contributions to this fabulous community.

And there it is, my reflections on the transformations of my past year. Hardly Hemingway-esque, but veracious nonetheless.

Tuesday, August 21, 2012

My Backwards Approach to Inverse Functions


Joe "Math Guy" was one of the first lessons I ever created. I drew this comic strip 'hook' for a sample class that I taught on inverse functions during a job interview. Years later, it's still one of my favorite lessons to teach.

One problem with algebra is that there is often a disconnect between the meaning/understanding and the computations/doing. We try our darndest to bridge the gap between the two, but I find that the meaning often gets muddied by cumbersome symbolic computations. For me, I like the way inverse functions lend themselves to the meaning first, and symbolic abstraction second. And when I do it well, a beautiful aha moment can occur.

Step1: Start Simple.

  • Functions are a series (composition) of one or more actions (functions) that maps one object onto another (as long as each input is related to only one output). For example, "Take something, add two and then multiply by 5," is a function. [It's also important to note that symbolic notation can differ in representations of the same function: like 5x + 10 and 5(x + 2). Why?]
  • Inverse functions are a series of reverse actions that undo the actions of a function. So, "Divide by 5 and then subtract 2," would be the inverse of the above function.
  • A function and its inverse, when composed together (in either order), always 'do nothing'.
Then we practice finding inverses of simple functions by first identifying the sequence of actions and reversing it. It's wonderfully intuitive and students 'get it' right away, just as long as Joe and I keep it relatively simple. Challenges at this point come in the form of four and five step functions, and not rational and quadratic curveballs.


Step 2: Complicate Things

Suddenly we find ourselves confronting rational functions and functions with multiple x's and our intuition begins to meet its match. At this point either I or someone in the class will throw up their hands and beg for a methodical way. I'll mention that one of my colleagues told me that I could just solve for x and that would be my inverse function. Dubious, but worth a shot. And so we try it, and yes it works. WHY??? Will that always work? What is going on?

Why is finding an inverse like solving an equation?

It is at this point that we talk about notation and graphs and all the algebraic aspects of inverse functions, keeping a tight grip on meaning: inverse functions 'undo' functions... no. 1 application for us right now? solving equations.

Have you noticed that we have not yet encountered any functions that don't have inverses? We do a lot of practice with functions that do have inverses before we even think about ones that don't.

Step 3: Complicate Things Again



So, now Joe finds himself confronted with two more functions and builds two more function machines. The problem is, Joe just cannot get back all of the numbers he threw into the original function! Why not?


What's wrong with these inverse machines? Is there any way we could tell in advance that these functions would have inadequate inverses? Is there any way to compensate for the missing values?




I purposely try to stay away from formal language at the beginning of this topic, but suddenly there is a lot of talk about inputs and outputs and mapping two inputs onto the same output. So the formal definitions come out, and lo and behold, they don't seem like jibberish.

If I'm lucky, something wonderful happens. They see a connection between this new topic and what they've been doing all along (solving equations). MAYBE they begin to appreciate the need for abstraction, formalization, and making compensations for small discrepancies.

And when that happens, my head rests peacefully on my pillow at night.