Category Archives: Problem Solving

July 18, 2012, 9:44 am

For proofs, just click “play”

This week I am adding to the playlist of screencasts for the inverted intro-to-proofs class I first mentioned here. There are seven chapters in the textbook we are using and my goal is to complete the screencasts for the first three of those chapters prior to the start of the semester (August 27). Yesterday I added four more videos and I am hoping to make four more tomorrow, which will get us through Chapter 1.

The four new ones focus on conditional (“if-then”) statements. I made this video as the second video in the series as a prelude to proofs, which are coming in Section 1.2 and which will remain the focus of the course throughout. Generally speaking, students coming into this course have had absolutely no exposure to proof in their background with the exception of geometry and maybe trigonometry, in which they hated proofs. Watch a part of this and see if you can figure out my …

July 10, 2012, 11:38 am

Inverting the transition-to-proofs class

By Robert Talbert

When I see the first back-to-school sales, I know it’s time, like it or not, to start prepping classes for the fall. This fall I am teaching two courses: a second-semester discrete math course for computer science majors and then two sections of “Communicating in Mathematics” (MTH 210). I’ve written about MTH 210 before when I taught it last fall. This fall, it’s going to be rather different, because I’m designing my sections as inverted or “flipped” classes.

If you’ve read this blog for any length of time, you know I’ve worked with the inverted classroom before (here, here, here, etc.). But except for a few test cases, I haven’t done anything with this design since coming to GVSU. I decided to take a year off from doing anything inverted last year so I could get to know the students and the courses at GVSU and how everything fits together. But now that I have the lay of the land, I…

June 12, 2012, 7:00 am

Misunderstandings vs. misconceptions

By Robert Talbert

The first speaker in the Model-Eliciting Activities (MEA’s) session Monday morning said something that I’m still chewing on:

Misunderstanding is easier to correct than misconception.

She was referring to the results of her project, which took the usual framework for MEA’s and added a confidence level response item to student work. So students would work on their project, build their model, and when they were done, give a self-ranking of the confidence they had in their solution. When you found high confidence levels on wrong answers, the speaker noted, you’ve uncovered a deep-seated misconception.

I didn’t have time, but I wanted to ask what she felt the difference was between a misunderstanding and a misconception. My own answer to that question, which seemed to fit what she was saying in the talk, is that a misunderstanding is something like an incorrect interpretation of an idea …

February 27, 2012, 8:00 am

Encountering abstraction with clickers

By Robert Talbert

I had the great pleasure this weekend of leading a session at Math In Action, which is Grand Valley’s annual K-12 educators’ conference. My session was called “Classroom Response Systems in Mathematics: Learning math better through voting” and was all about the kinds of learning that can take place in a class where active student choice is central and clickers are mediating the voting. (Here are the slides.)

It always seems like a bait-and-switch when I do a “clicker” workshop, because although people come to learn about clickers, I don’t really have much to say about the technology itself. As devices go, clickers are about as complex as a garage door opener, and in fact they work on the same principle. There’s not a lot to discuss. So instead, we spend our time focusing on the kinds of pedagogy that clickers enable — which tends to excite teachers more than technology does.

The a…

September 15, 2011, 8:52 pm

Using clickers for peer review of proofs

By Robert Talbert

http://www.flickr.com/photos/unav/

Right now I’m teaching a course called Communicating in Mathematics, which serves two purposes. First, it’s a transitional course for students heading from the freshman calculus sequence into more theoretical upper-level math courses. We learn about logic, how to formulate and test mathematical conjectures, and we spend a lot of time learning how to write correct mathematical proofs. And therein is the second purpose: The course is also labelled as a “Supplemental Writing Skills” course at Grand Valley, which means that a large portion of the class, and of the course grade, is based on writing. (Here are the specifics.) It’s a sort of second-semester, discipline-specific composition class. (Students at GVSU have to have two of these SWS courses, each in different…

May 26, 2011, 8:01 pm

Any questions about this video?

By Robert Talbert

As part of preparing for our impending move from Indy to Grand Rapids, my family and I have made a couple of visits to the area. These by necessity combine business with pleasure, since our three kids (ages 2, 5, and 7) don’t handle extended amounts of business well. On the last visit, we spent some time at the Grand Rapids Childrens Museum, the second floor of which is full of stuff that could occupy children — and mathematicians — for hours. This “exhibit” was, for me, one of the most evocative. Have a look:

Spinning table from Robert Talbert on Vimeo.

I asked this on Twitter a few days ago, but I’ll repost it here: In the spirit of Dan Meyer’s Any Questions? meme, what questions come to mind as you watch this? Particularly math, physics, etc. questions.

One other thing — just after I wrapped up the video on this, someone put one of the little discs rolling on the turntable…

December 16, 2010, 2:30 pm

A problem with "problems"

By Robert Talbert

I have a bone to pick with problems like the following, which is taken from a major university-level calculus textbook. Read it, and see if you can figure out what I mean.

This is located in the latter one-fourth of a review set for the chapter on integration. Its position in the set suggests it is less routine, less rote than one of the early problems. But what’s wrong with this problem is that it’s not a problem at all. It’s an exercise. The difference between the two is enormous. To risk oversimplifying, in an exercise, the person doing the exercise knows exactly what to do at the very beginning to obtain the information being requested. In a problem, the person doesn’t. What makes an exercise an exercise is its familiarity and congruity with prior exercises. What makes a problem a problem is the lack of these things.

The above is not a problem, it is an exercise. Use the

November 29, 2010, 9:00 am

What correlates with problem solving skill?

By Robert Talbert

About a year ago, I started partitioning up my Calculus tests into three sections: Concepts, Mechanics, and Problem Solving. The point values for each are 25, 25, and 50 respectively. The Concepts items are intended to be ones where no calculations are to be performed; instead students answer questions, interpret meanings of results, and draw conclusions based only on graphs, tables, or verbal descriptions. The Mechanics items are just straight-up calculations with no context, like “take the derivative of \(y = \sqrt{x^2 + 1}\)”. The Problem-Solving items are a mix of conceptual and mechanical tasks and can be either instances of things the students have seen before (e.g. optimzation or related rates problems) or some novel situation that is related to, but not identical to, the things they’ve done on homework and so on.

I did this to stress to students that the main goal of taking …

November 12, 2010, 4:04 pm

This week in screencasting: Optimization-palooza

By Robert Talbert

My calculus class hit optimization problems this week — or it might be better to say the class got hit by optimization problems. These are tough problems because of all their many moving parts, especially the fact that one of those parts is to build the model you plan to optimize. Most of my students have had calculus in high school, but too many calculus courses in high school as well as college focus almost primarily on algorithms for computation and spend little to no time with how to create a model in the first place. Classes that are so structured are doing massive harm to students in a number of ways, but that’s for another post or two.

Careful study of worked-out examples is an essential part of understanding optimization problems (though not the only part, and this alone isn’t sufficient). The textbook has a few of these. The professor can provide more, but class time really …

August 17, 2010, 4:01 pm

Why change how we teach?

By Robert Talbert

Sometimes when I read or hear discussions of innovation or change in teaching mathematics or other STEM disciplines, whether it’s me or somebody else doing the discussing, inevitably there’s the following response:

What do we need all that change for? After all, calculus [or whatever] hasn’t changed that much in 400 years, has it?

I’m not a historian of mathematics, so I can’t say how much calculus has or hasn’t changed since the times of Newton and Leibniz or even Euler. But I can say that the context in which calculus is situated has changed – utterly. And it’s those changes that surround calculus that are forcing the teaching of calculus (any many other STEM subjects) to change –radically.

What are those changes?