kitchen table math, the sequel: smiling fruits: another disastrous tutoring session

## Wednesday, February 21, 2007

### smiling fruits: another disastrous tutoring session

The latest topic was "Matrixes [sic] and Arrays." I've learned to stop making assumptions about the content, so even though I momentarily wondered if math now included computer science or programming, I pushed it out of my mind.

I can't reproduce this on blogger, so please try to visualize it. I looked at the worksheet and saw at the top four fruits in two columns and rows (fruits with little smiley faces, but believe it or not, that didn't add to the stupidity of the worksheet): from left to right and top to bottom, they were a banana, an apple, a strawberry, and a pear. The graphic was captioned, "This is a matrix!"

Uhm, okay, I suppose it is. It's not very mathematical in any sense of the word, however. But back to the worksheet. The next graphic was similar to the first, except that it had brackets around the fruits (still with smiley faces). It was captioned, "This is the same matrix!"

Next was the same matrix, with a huge 2 x in front of it, and after it, an equally huge = ?

Ah, so we finally have math! And beneath it was the same graphic, but with another graphic in place of the question mark: from left to right, top to bottom, two bananas, two apples, two strawberries, and two pears.

As Mr. Mackey would say, M'kay. (Recall that this is the 8th grade.)

So we have a "You do one!" exercise, where we have six vegetables in three rows and two columns: a head of lettuce, a stalk of broccoli, a bunch of asparagus, a clump (that's the only way to describe it) of green beans, a tomato (don't be picky), and a mess of greens (okay, so I'm from Kentucky -- that's what we call it, though I suppose they're probably supposed to be "field greens" or whatever the currently fashionable euphemism is), preceeded by a huge 3 x and followed by a huge = and the instructions: "Draw your answer below!"

Now wait a minute. So are they supposed to draw three heads of lettuce, etc., and are they supposed to draw the smiley faces too? Wouldn't this have been simpler just using numbers or variables? I mean, isn't that why we use numbers and variables in the first place? So I sat there while Ricky painstakingly drew little bunches of asparagus and so forth.

Then we were ready for the next set of worksheets. Interestingly, the graphic looked exactly like the first matrix graphic: a banana, an apple, a strawberry, and a pear, with the same smiley faces. It was captioned, "This is an array of fruits!"

Well, sort of. I suppose. Maybe. I see where she's trying to go (actually, I don't know that the teacher is producing these idiotic worksheets -- she may be getting them from somebdy else). Ricky looked at me. I looked at him. We looked at the worksheet. Ricky said, "What's the difference?"

(For those of you who aren't programmers, an array is a lovely thing that saves us many many many tears and hours of work. An array, basically, is a megavariable, if you will. It allows us to treat a set of related variables as if it were one variable, so if we have to do the same thing to a set of related variables, we only have to write, say, forty lines of code instead of forty lines of code for every related variable in the array.)

I said, "Ask me in a few minutes."

He said, "You don't know?"

I said, "I know what an array is, yes, but I'm not sure where this is headed. So ask me in a few minutes."

Then below the graphic was a question. It said something like, "If you were going to make a fruit pie, what would you buy at the store?"

Come on. She believes the correct answer is "fruit," or "a bunch of different fruits," or something to that effect, but how many pies has your average 8th grader made, and why would she assume her students knew anything about making pies? Then for the few students who have made a pie and have some idea of what goes into one, there are other answers that are also correct, like flour, etc. Then beneath the space left for the answer, there was (for the first time, I might add) a working definition of an array, well, sort of. "When we just need all kinds of different fruit, we use an array!"

I was getting a headache. I had my head in my hands, trying not to cry. This was so, well, stupid and useless it was driving me nuts, and I'm not the one who has to finish it and turn it in. So when Ricky was done with it, we went back to linear equations and all that formalism stuff (he still hates it, but he does it, at least).

Oh. Did I mention that I've met the teacher? Did I mention that the reason she wanted to meet with me was because she's concerned? Did I mention that the reason she's concerned is because Ricky is doing so well and she's afraid it will make the other students feel bad?

Catherine Johnson said...

You can't be serious.

She really wanted to meet you because Ricky is doing too well?

What did you say?

Catherine Johnson said...

It's probably time to riot in the streets.

Catherine Johnson said...

I think we've pretty much exhausted all of our diplomatic options.

SteveH said...

Matrixes?? Is this a book? Who wrote it?

Everyday Math calls things that are lined up in rows and columns "arrays". I have also seen references to the term "matrix arrays". There is some confusion here. In programming, arrays are one dimensional and matrices are two-dimensional or higher. (One could call an array a matrix with one column or row.) I can deal with a certain amount of ambiguity, but their definition of arrays as something you use when you need all kinds of different fruit is harmful.

This is 8th grade? Is this an official algebra course?

KDeRosa said...

and a mess of greens (okay, so I'm from Kentucky -- that's what we call it, though I suppose they're probably supposed to be "field greens" or whatever the currently fashionable euphemism is)

This reminds me of a diner scene from the movie Intolerable Cruelty:

Wrigley: Uh, I'll just have a, um, salad, please. Um, baby field greens.

Waitress: What did you call me?

Wrigley: Uh, no, I-I... I-I didn't call you anything.

Wrigley: Yeah. Do you... Do you have a, uh, green salad?

Waitress: What the f*ck color would it be?

Wrigley: Why are we eating here?

Waitress: What's his problem?

Miles Massey: Just bring him an iceberg lettuce and a mealy tomato wedge smothered with French Dressing.

Anonymous said...

Ricky is doing so well and she's afraid it will make the other students feel bad?

Time for Ricky to get out of that class.

Doug Sundseth said...

I despise "math" that requires drawing pictures of random objects or (worse) people. I know of no research linking the ability to draw a recognizable object with the ability to do math.

FWIW, at first I didn't understand your questions about whether matrix math was actually math. After all, linear algebra is a fine subject. I suspect that this is just a misguided attempt to introduce content at an inappropriate time. I'm sure it will be glossed over without actual instruction several more times in the next few years.

I just want to see what the cross product of two fruit matrices/matrixes is.

ps. "Matrixes [sic] and Arrays."

stet

The plural of "matrix" in English is either "matrices" or "matrixes". Similarly, the plural of "index" is either "indexes" or "indices".

The regular plural being easier for a novice to understand, I think it an entirely defensible choice.

Catherine Johnson said...

I'm sure it will be glossed over without actual instruction several more times in the next few years.

ditto that

Ben Calvin said...

Everyday Math calls things that are lined up in rows and columns "arrays".

I can only assume this is an attempt to confuse the students enough they can never learn Visual Basic.

Unknown said...

"The plural of "matrix" in English is either "matrices" or "matrixes". Similarly, the plural of "index" is either "indexes" or "indices"."

For those who believe that the word "data" is a singular noun, perhaps. And don't get me started.

Catherine Johnson said...

I can only assume this is an attempt to confuse the students enough they can never learn Visual Basic.

a worthy goal