In which I rant about an illiterate from Daily Kos
So I notice a handful of people came to this blog from the Daily Kos, which doesn’t happen, ever. So I go look. And I’m there.
In a discussion about education, a commenter named “Punditician” decides to give an example of a math teacher who went to education school and doesn’t know math. And he uses? me? What?
This week I blogged:
Punditician cites it as some sort of proof about dumb math teachers. Girlfriend’s a moron.
- She’s badly off topic. Trolling doesn’t require a whole lot of intelligence, just patience to keep stoking the flames. Read the essay, if you really want to. The comment, even if it were accurate, doesn’t follow.
- She’s badly mistaken. I’m not an education major.
- She didn’t read. It takes about 5 minutes of poking around this blog to figure out both who I am and what I’m doing here.
- She’s wrong about the math. It is not particularly complicated (I’ll return to that), but basic? Absolutely not.
And she’s wrong about my math. I am not the best, far from it, and I have gaps (including linear). But I consider myself fairly solid.
So why don’t I have a good grasp of matrix multiplication?
First, I can multiply. It is the “why” question that I asked. And frankly, I don’t multiply matrices. Not daily, or weekly, or once a year. It’s not something I need to do.
My first linear course was in 1984, and my last was in 1986. The first was one of my least favorite math classes. Can’t say I gave it reasonable attention. And the second was just meh. That part of my education was at an engineering school. Not an excuse. But an explanation, at least a little bit. Our math courses, some of them, were weird. One day I still need to take a normal pde. That was the weirdest. (Ask me why?)
I’ve encountered matrix multiplication, occasionally, since, but have not given it much thought. Perform the operation, move on.
A lot of what I do well, I have reconsidered as I begin to teach a topic for the first time. My arithmetic is better than when I started teaching. As is my algebra. Trig. Geometry. Let’s not start on counting. And logic.
This year I am teaching precalc. Two of us redesigned the course, and we decided to expand a unit on systems of equations, early. It helps for the kids to see something new that turns out to look wildly different, but is accessible. And we packed the end of the course (Spring) with things they will need for calc (series, sequences, limits, a second, harder look at trig, etc). In any event, I am actually teaching matrix multiplication for the first time.
So why left to right? Why row by column? Why non-commutative? And what is a model that is accessible to kids? The transformations will follow, not precede, teaching the operation. (if you are not sure why, try writing a set of lessons that develop the topic from scratch. You’ll see.)
Why didn’t I just check wikipedia, or my old notes (which I might have?) or an old text (there’s one on my shelf) or the kids’ text book? First, kids’ text book for resource? Never. And as for the others, I could have. But I appreciate the richness of the discussion that often happens here. Finally, I like to tell the kids that I ask for help. They sometimes see me as the authority in the room, rather than the math. It’s good to remind them.
Not everyone can get away with that. The kids need to think I know my stuff before I can admit to gaps. But they do. Parents do. As I was checking my anger at Punditician’s ignorant comments, I remembered how many parents have tried to get their kids into my classes. I thought about how many scientists, engineers, and even mathematicians have wanted their kids to learn from me.
And then I went back to her comments. Just more lousy teacher bashing. And off-topic at that. I shouldn’t have taken so personally.