Means Extremes – Balancing the Means and the Ends of Math Class

I have been seeing this play out in my geometry classes each of these past six school years. It’s been a tricky problem for me to figure out and once I started to see what was going on, it became even harder for me to communicate it. I think I am ready to try.

Each year, a fresh cohort of young people come in straight from Algebra I. In theory, I can assume that they are fully loaded with algebra skills and thought-processes that will support them through their study of Geometry. There is one glaring hole in their understanding which I attributed to the overall youthfulness of many of my geometry students. They are 13-15 years old and, for the most part, their math experiences lack a significant diversity. So, I am able to give them a pass on some of the ways they are still developing as math learners.

But then I saw the same deficiency in my calculus students that I am only seeing now because this is my first year teaching calculus. Suppose that I give a geometry student this problem and ask them to find the angle measures of each angle.

Taken from Holt Geometry - Pg 181

Taken from Holt Geometry – Pg 181

Or suppose I gave my calculus students this problem.

Soda Can Problem

Let’s add in as evidence that the Geometry students are used to application problems that look like this:

Taken from Holt Algebra I - pg 478

Taken from Holt Algebra I – pg 478

And that the calculus students have spent a lot of time looking at pages like this:

Taken from Holt Algebra II - Pg 580

Taken from Holt Algebra II – Pg 580

The primary difference between the work I’m asking my Geometry and Calculus students to complete and the work that they are used to in the Algebra I and Algebra II is in the latter the equations are provided and in the former, the students are required to write the equation.

This is no small point. No side conversation. I am not splitting hairs. I am convinced this is a big difference.

Let’s go back to our Geometry problem.
Taken from Holt Geometry - Pg 181 First and foremost, recognize that there is very little natural or intuitive about this set-up as a whole. There is very little reason why angle measures are represented with algebraic expressions. The variable “x” doesn’t represent any actual value and so, the students are left to their abstract understanding of how equations are built in order to solve this problem. Their previous experience hasn’t really prepared them for this. Overwhelmingly, their mathematical experience leading up to this point has trained them to know how equations are solved.

Let’s expand this to our calculus team (of 23) of whom I noticed only about 8 or 9 who seemed comfortable modeling volume and surface area with equations and then engaging the formulas. So, even among our most talented high school students, there is a problem with the use of equations as modeling tools. Once they have them, they can operate with them wonderfully, but they struggle when it comes to writing them to specifically to match a specific situation. And beyond that, checking the accuracy of the model and then making sense of the product once they are done.

Herein lies the major issue: the paragraph above highlights a variety of skills that students (at all levels, from what I can tell) struggle with. They seem to struggle with them because they aren’t practicing them. But those are the skills that actually make mathematics worth doing to EVERYONE. The ability to do complex arithmetic on a rational or logarithmic expressions is something that is going to come in handy to people for whom formal mathematics is going to extend into their post-secondary lives. This isn’t a high percentage or our students, but these skills constitute a high percentage of the problems in our textbooks.

On the other hand, being able to recognize a situation as linear, quadratic, logarithmic or rational and have a sense of how to model that in order to make some predictions? That is something that could be valuable to a higher percentage of people outside of school.

I think that we need to recognize that the specific skills that we are teaching our math students are a means, not an end. They are the tools, not the final product.

The real goal is for the students to explore a situation, recognize the mathematically significant parts and use their math tools to model the situation strategically to help them achieve their goal. In addition to our student being better, more confident, flexible and patient problem-solvers, it seems like we’d also hear “when am I ever going to use this?” a whole lot less.

The Fear of Trying

I teach a calculus class. It’s the first time that I’ve done that. I have a story about them.

Yesterday, I introduced the idea of limits, which, according to them, was the first time any of them had ever had limits discussed in any way in a math class. After a short lecture-style introduction about the basic idea of limits, the notation, and some anecdotal comments, I unleashed them on this handout. I was not going to collect handout. I wasn’t going to fasten any points to this handout. They knew both of those things. I gave them 12-15 minutes to try the handout. This is where life gets interesting.

About 6 minutes into the time, I began walking around to look at some work. There are 23 students in the class. I estimate that 17 of them had, for as many as 10 minutes had done zero math, but had done a fantastic job of transferring the table from the handout into their notes. I was flabbergasted. They had spent 10 minutes drawing a table. These calculus students (who, by most traditional metrics represent the most confident and talented math students in our student population) wouldn’t try the math.

Their years of math class “success” had thought them two things that created this scenario: A. Stay busy, or at least look busy. Teachers get  mad at students who sit around. And B. The only answers worth writing are correct answers. If you don’t know the correct answer, don’t write anything.

These students didn’t want to write a wrong answer. They didn’t know the right answers, so they opted to create incredibly high quality tables in their notes. Their explanation for this usually included the statement, “Well, I didn’t know how to do it.”

I responded with, “Of course you don’t know how to do all of this, I introduced it 10 minutes ago. I’m just looking for you to give it your best try to see where your thoughts are taking you right now.”

After about a 5 minute pep talk, they tried, and much to the surprise of most of them, most of their attempts where actually correct answers.

And make no mistake, this isn’t just calculus. This isn’t just the traditionally-successful math students. Anyone who has taught a math class has seen students who know that they don’t know how to solve a problem and would much rather leave the problem blank than put something down that is wrong. The wrong answer seems worthless.

It seems that we have conditioned our students into thinking that an answer on a page is an opportunity for judgement. If they write something on the page, I’m going to have the final say whether it is right or wrong. Wrong answers are bad. Grades go down because of wrong answers. This mentality would prefer to leave an answer blank. At least if it is blank, you can pretend that you simply need more time.

Instead, we should be showing our students that an answer on a page is the beginning of a conversation that ends with them learning something new. It could be that the answer on the page confirms that they have already learned (which makes for a short conversation). It could also be that the answer on the page demonstrates that more learning is needed, and the answer on the page is the window into the confusion, clues to the misconceptions or the missing understanding. When learning is incomplete, perhaps the BEST thing a student can do is show us his or her very best wrong answer.

But first we have to teach our students that anytime they put what is in their heads on paper, there is value. There is value in a correct answer and there is value in an incorrect answer. It’s true that they are valuable for different reasons, but they push toward the same end. The authentic learning of mathematics.

Perhaps if we can reestablish the value of an incorrect answer, we can do something about this incredibly pervasive fear of trying.

The Snickers Problem: The Aftermath

What math class looked like this week

What math class looked like early this week

There is nothing quite like watching the students get there hands dirty with the mathematics. This is especially true when the students are literally getting their hands dirty. In this case, it was with caramel, chocolate and nougat.

Here is some of the aftermath of the students exploring The Snickers Problem. (Check it out for a description.)

Snickers #2

To me, the value of this assignment lies in its ability to draw the students in. This problem featured 100% engagement. It featured the type of proportional reasoning that shows up in endless amounts in our unit on Similarity and Dilations. The students were analyzing the size comparison of a fun-sized Snickers and predicting the number of peanuts.

Others preferred the more antiquated utensils...

Others preferred the more antiquated utensils…

This was a fantastic activator. Formal proportional reasoning is difficult for many students, but informal proportional reasoning is intuitive. Many of the students found that their predictions were pretty close. (Although, we did find some Snickers that had remarkably low numbers of peanuts.)

Knife and fork worked for some

Knife and fork worked for some

And the fantastic questions that come up when students are thinking mathematically.

Is this prediction close enough?

What do we do about half-peanuts and peanut pieces?

Their prediction was right, but ours was wrong… but we predicted the same thing! Our snickers had different number of peanuts!

These are all evidence of students having to have an experience with the mathematics. That’s something I’d like to see more of.

Mathematical Creativity: Multiple Solutions to the Pencil Sharpener Problem

I enjoy watching students exploring a problem that forces them to come up with their own structure for solving it. Today, a group got a chance to mess around with The Pencil Sharpener Problem, which is a problem I posted a month or so ago. (I’ll leave you to read it if you are curious what the problem is.)

From my perspective, what makes this problem interesting for the students is the ease with which it is communicated and the complexity with which is it solved. It seems quite easy. The answer is fairly predictable, but the students quickly found out that if they were going to solve this problem accurately, they were going to need two things:

1. A way to organize their thoughts and,

2. a way to verify their answer.

As long as the solution process included those two things, the students ended up fairly successful in the process of this problem.

I submit to you four examples of student solution structures. They all look different, but they all have one thing in common: The students could tell you with absolute certainty what was on the page and that they were right. (I withheld judgment from the correctness, but I will say that their final answers were all pretty much the same.)

This one includes a bit of a floor plan

This one includes a bit of a floor plan

In this first one, shown above, this pair of students decided to draw a floor plan with each of the pencil sharpeners (and the bucket they were tossing their leftover pencil nubs). The solution process progressed from there.

Guessing and Checking

Guessing and Checking

These two students are classic minimalists. They worked to guess-and-check, which requires a bit more skill than it might seem. They needed to decided what number they were going to guess (sounds like an independent variable) and how to check their answer (sounds like a function producing a dependent variable). They weren’t using the vocabulary. It didn’t seem to be a problem for them.

Guessing and Checking

Guessing and Checking

These two were a little more formal with their guess-and-check process, and they were using the terms independent and dependent variable. For the record, the time was independent and the number of pencils sharpened was the dependent variable.

A graph of multiple equations (where the solution does not include finding an intersection point)

A graph of multiple equations (where the solution does not include finding a single intersection point)

These two struggled a bit to convince themselves that they were on the right track as they completed this graph. They were discussing the need for the graph to be accurate (essential), how to interpret the three sets of points (one set to represent each pencil sharpener). Eventually, the were able to find the spot on the graph when the numbers added up properly. The number along the x-axis represented the final time. (Once again, they didn’t call time the independent variable, but it looks so nice along the x-axis, doesn’t it?)

Each of these students would have likely looked at the others with confusion, yet their answers largely agreed. What it required for them to solve it wasn’t me, as teacher, telling them how. On the contrary, it required me, as facilitator, designing a problem they would engage with and then giving them the resources to make sense of the problem with each other.