My “First” Mathematical Problem and What It Means

I am inspired, by several previous blog entries, to write about my own mathematical awakening, and what I’ve learned from reflecting on it.

I went to New York City Public Schools, in the Bronx.  I always enjoyed arithmetic and mastered it easily.  I remember not knowing what ‘fractions’ were, but don’t remember learning about them, any more than I remember learning to read.   The understanding came to me naturally, and I hardly noticed the process.  Even first year algebra didn’t seem like a learning process, more like a set of exercises.  So I had mastered a lot of mathematics (well, a lot of algorithms) before I really understood what it was I was learning.

A revelation came in ninth grade, when I was 13.  Ms. Blanche Funke, a good math teacher in JHS 135, took some of us during lunch and organized us as a math team, to compete against other local Junior High Schools.  Now this is work I have since spent decades doing, and I know now what could have been done.  But Ms. Funke didn’t quite.  Her idea was to give us advanced training in textbook algebra—not to find ways to make us think differently about that same algebra.

So she gave us the definition of an arithmetic progression, and the standard formulas.  And a problem something like: “Insert 3 arithmetic means between 8 and 20.”  I loved this work.  Plug into one formula, get the common difference, then plug into another formula and get the three required numbers.  I could see what I needed to do and took joy in starting the work.

But next to me was my friend David Dolinko, and he was busy drawing something in his notebook—some diagram of a molecule in chemistry.  (Professor Dolinko has lately retired from the UCLA School of Law).  I poked David.   “C’mon.  Let’s do this problem.  It’s fun!”

David looked at me, as if annoyed at the interruption:  “Oh, I did that already.  Eight, eleven, fourteen, seventeen, twenty.”  And went back to his drawing.

That moment changed my world.  Suddenly I realized that these formulas had meaning, were trying to express something.  They were expressing that the numbers were ‘equally spaced’.  So David could just pick them out—the numbers were small—and didn’t have to bother with the algebra.  Algebra has meaning.  And if you know its meaning you can use it more effectively.   Suddenly, instead of black and white, I saw the world of algebra in color.

I thought about this a long time.  The colors attracted me more and more.  I wasn’t just good at mathematics.  I enjoyed it, and enjoyed being good at it.

Well, the next year I was still sitting next to my friend David, in the last seat, last row of a classroom in the Bronx High School of Science.  We were taking geometry, the classic neo-Euclidean syllabus, taught by one Dr. Louis Cohen.  He was a somewhat impersonal teacher, or so we thought, but a master of his discipline.  And of teaching it.  So one day he had covered (I don’t remember how) the theorem that the angles of a triangle sum to 180 degrees.  The lesson had gone quickly, so he filled the time with some ‘honors’ problems: the sum of the angles of a quadrilateral, some problems with exterior angles, and so on.  And to cap it off, he drew a five-pointed star on the board:

Not a regular figure, but just any one that came to hand, using the usual technique of following the diagonals of an imaginary pentagon.  He then asked for the sum of the angles at the points of the star.

My hand shot up, seemingly of its own accord.  “180 degrees,” I said, without quite knowing why.  And to my horror, Dr. Cohen strode calmly down the aisle to my desk, with a piece of chalk in his hand, handed me the chalk, and asked me to explain to the class how I had figured this out.  But I didn’t know how I had figured it out.  I just saw it, with intuitive clarity.  What was I going to do?

I was lucky that we sat in the back of the room.  As I saw him coming towards me, I began to analyze my own thoughts.  And as I walked to the front, I figured out what to say.  To this day I remember my hand trembling and my voice shaking as I pointed out certain triangles, certain exterior angles, and got the angle measures all to ‘live’ in the same triangle.  Dr. Cohen praised me, then gave a slicker version of the proof that must have clarified it for the other students.   Of course, there are better ways even than his to prove this statement.  If the reader can’t think of a nice proof offhand, take a look (for example) at   https://www.khanacademy.org/math/geometry/hs-geo-foundations/hs-geo-polygons/v/sum-of-the-exterior-angles-of-convex-polygon (accessed 6/2018).   The argument can be adjusted to cover non-convex polygons.

Why is this important?  Well, it is important for us to understand that the language of mathematics is a language of thought.  And that thought is synonymous with intuitive thought.  We sometimes get caught up in the expression of our intuitions, and fail to go back and make clear, even to ourselves, what we are talking about.  This phenomenon has deep implications for teaching.  How we do this, how we know it has happened, how we integrate it into the teaching of mathematics as a forma language, are all questions we must struggle with.  But they are not questions that we can beg.  We must somehow be sure that students can eventually understand our results on an intuitive level, whether or not we communicate with them on this level directly.   Without that, we are teaching algorithms—even algorithms of proof—and not mathematics.

I invite readers to contribute their ideas to this blog about how to make mathematics accessible on an intuitive level.

 

 

 

 

This entry was posted in Active Learning in Mathematics Series 2015, K-12 Education, Mathematics Education Research, Student Experiences and tagged , , , , . Bookmark the permalink.

5 Responses to My “First” Mathematical Problem and What It Means

  1. Leslie Horton says:

    Your teacher did not just throw the problem at you out of the blue. You had been studying the basic algorithm and then had gone through other algorithms before the five point star problem was on the board.

    Even my most “unmathy” students can solve this type of problem if led gently into it.

    • msaul says:

      In fact he did throw the problem in out of the blue. All we had studied was the sum of the angles of the triangle, which he had proved maybe 30 minutes before giving this problem. He was a brilliant teacher, and would challenge us like this.

      Going a bit deeper, what your comment says to me is that the same problem can be routine (for “unmathy” kids) or challenging, depending on the pedagogical context. Or: you cannot tell whether a question is a problem or not until you look at the context. The word ‘problem’ is a term for a relationship between a question and the person being asked the question.

  2. Roderic Taylor says:

    I actually do remember learning about fractions as a child. I was working out division. I divided two circular pies into three equal pieces, and saw each piece was 2/3 of a pie. I did some similar examples until I saw that a divided b was a/b. Then it hit me. That fraction bar was a division sign! And then it occurred to me that when I calculated 3 divided by 5 is 3/5, what I was really saying was 3 divided by 5 is 3 divided by 5. So how was I saying anything at all?

    I enjoyed your article and it makes an important point. It’s a challenge to get students to see the meaning math, so it’s not just applying a bunch of meaningless algorithms.

  3. Joe Quinn says:

    My mathematical awakening happened significantly later. If you want the long version you may have to buy me a drink sometime, but here is a short version.

    Math came easily to me from a young age. Perhaps part of that is hard wiring but I have a theory about another contributing factor. My older brother has a learning disability, and for him to keep up in school required my mom to explain every math concept to him at length and in as many ways as she could think of. She often did this at night while my brother was getting ready for bed, and I would be up in the top bunk listening and making connections. So by the time I got to school it was all old hat.

    The down side to that is: I found math class so easy that it bored me. I was notorious in high school for sleeping in AP calculus, being woken up by the teacher who hoped to put me on the spot, solving the problem on the board effortlessly, and going back to sleep. Not long after heading off to college as a math major on a nice scholarship, my boredom and rebelliousness got the better of me and I spent the next several years in and out of school, then exploring other interests and alternative lifestyles.

    When I was 27, I decided it would be nice to make my mom happy by going back to school to finish my BA in math. The original plan was: do that, prove to the world that my brain still worked, then go back to what I’d been doing in spite of the diploma, refortifying my rejection of the popular definition of success. But when I took abstract algebra, I had an awakening similar to what Mark described. I started reading sections of my textbook that weren’t part of the course. I started trying out my own ideas, researching what past mathematicians had figured out about them before me, and pushing my brain in new directions that not only fascinated me but gave me a whole new appreciation for life. I realized (at long last) that math is about exploration and discovery, not just about computing known answers to puzzles for societal recognition of one’s intelligence.

    So I switched from a BA to a BA/MA, then did a PhD, then a postdoc. But I found that my life experience was quite radically different from that of most research mathematicians I met, to the point where it was often difficult to relate to them. In the meantime, I’d begun to harbor some animosity about the fact that it took so long for me to find out what math really was. What if someone had shown me this before I got bored? Would I have published my first article 10 years earlier? Would my life thus far have been less chaotic and painful? Would I be perfectly happy studying esoteric generalizations of abstract concepts that rarely find any application to the sciences, never mind public understanding? Wait … would that even be a good thing?

    Well, I try not to ask too many what-if questions and at the end of the day I have no regrets. But I decided that rather than continue as a research mathematician, I feel more fulfilled in a career focused on creating, for other people, the sort of experiences I would have appreciated when I was younger. Soon enough, I was lucky enough to get a job offer doing just that kind of work.

  4. ABHISHEK PANDEY says:

    Its important to have fun straightaway whether it is mathematics,engineering or simulation work. Fun comes with regular practice and that leads to development of thoughts amd ideas which ultimately leads the student into that domain and produce some extraordinary results.The word practice is very important and that can make a huge difference in anyones life. Practice with proper guidance and counselling can produce great results and will definately make anything wonderful !!! Including Mathematics

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