Archive for March, 2011
New MyMathLab Site For My 3E – Available To Copy
I have put together a MyMathLab course for the new edition of my Elementary & Intermediate Algebra textbook. I have set it up so you can copy it. Inside the course are 14 Chapter quizzes, 14 Chapter midpoint quizzes, 22 Student Learning Outcome (SLO) quizzes, 83 homework assignments, and announcements that can be posted/emailed to your students for Chapters 1-8. (The remaining announcements will be posted in the next week or so.)
The Course ID, and all important information can be found on this page on my web site.
If you do copy the course, please drop me a line through the Contact page on my website so that I can keep you apprised of changes I make and new features that become available. You can also reach me through that page if you’d like me to customize a course for you – cut out certain chapters, delete certain assignments, …
-George
I am a math instructor at College of the Sequoias in Visalia, CA. You can reach me through the contact page on my website – http://georgewoodbury.com.
So, I was at ICTCM this weekend … Help Wanted?
During the week I will be posting a series of blogs inspired by sessions I attended at ICTCM – including Wolfram|Alpha, Discussion Boards, Redesign, Inverting the Classroom, and Resampling in Statistics. I will also blog about things that happened outside of sessions, I came back with several ideas and projects. (Maybe this will take a couple of weeks.)
The most exciting topic to come up was introduced by my friend Susan McCourt from Bristol CC. She has an idea to create a blog site where we can have a pool of college math instructors blogging at a certain schedule (once a week, every 2 weeks, …) or have guest blogs as they fit. Blogging is a great way to share ideas and to learn, but it is difficult to blog on a daily basis. If you’d like to get involved, or if you know someone else that you’d like to nominate, leave a comment on this blog or reach me through the contact page at my web site – georgewoodbury.com. I’ll be helping Susan to get this off the ground.
-George
I am a math instructor at College of the Sequoias in Visalia, CA. If there’s a particular topic you’d like me to address, or if you have a question or a comment, please let me know. You can reach me through the contact page on my website – http://georgewoodbury.com.
Flipping the Class & Khan, Part 2
So, I went back and watched several videos at the Khan Academy last night. To be fair, there is more conceptual presentation than I thought. This makes me feel even better about sending my students to watch these videos. Yesterday’s blog shows the power of Web 2.0, blogging, & Twitter. I asked if I was missing something, and got lots of great feedback including from Jason with the Khan Academy team.
Where am I today?
I still feel that flipping the classroom is a worthy pursuit. There are lots of ways to get this done. The easiest way would be to flip the class in such a way that all of the students were working at the same pace on the same material. A motivating conceptual lecture could be given at the end of the class session, students could visit web sites for conceptual enrichment & how-to practice, with collaborative work in class the following day. There are variations that could work – written assignments for students to develop conceptual understanding at home, computerized assignments for drill practice, conceptual portions of the collaborative work. The Khan Academy videos could definitely be a tool utilized in this approach.
But is keeping everyone on the same pace the best way to flip the class? Isn’t there something to be said for allowing students to learn at their own pace? This is much harder to pull off, because it would then be impossible to give mini-lectures that conceptually motivated the topics. (Imagine 30 students in 30 different places – even if you could give all the mini-lectures there would be no time left for coaching/mentoring). So, we’re reliant on using the work of others to deliver the conceptual understanding or we must create all of the material ourselves. The best option is often the most difficult option.
Even after looking at the Khan Academy videos again, I don’t think that there is sufficient conceptual development there. It will be hard to find a one-stop shop that couples solid conceptual explanations of mathematical ideas along with practical how-to videos (which Khan does quite well) along with an arena for interactive student practice.
For me, I think the opportunity is there with MyMathLab. Depending on the book, there are videos that explain concepts & demonstrate how to solve problems. The homework & study plan, with all of its learning aids, can provide students with the quality practice they need. I’m going to try it in the fall, using the “all on the same pace” approach. I may need to supplement with more how-to videos, either from other sources online or by creating my own. I may need to develop some conceptual videos & materials. But I’ve got all summer, right? I wonder if I’m stumbling into one of those a-ha moments?
Let’s keep the conversation going. Please leave your opinion as a comment, or you can reach me through the contact page at my web site – georgewoodbury.com. I’d still like to hear from those of you who have experience in flipping the classroom.
-George
I am a math instructor at College of the Sequoias in Visalia, CA. Each Wednesday I post an article related to General Teaching on my blog. If there’s a particular topic you’d like me to address, or if you have a question or a comment, please let me know. You can reach me through the contact page on my website – http://georgewoodbury.com.
Can the Khan Academy flip a classroom?
Salman Khan’s recent TED talk has generated a lot of buzz. (You can check out the video here.)
At one point he mentioned how the Khan Academy videos are being used to “flip” the classroom, and that’s when I got a little worried. I like the idea of flipping the classroom – having students learn concepts via video outside of class and using class time to work on problems, turning the teacher into a mentor or coach. My friend Mike Sullivan has done this with great success at his college. In this environment, there is more time for collaborative learning and one-on-one instruction. I feel that this can really help students to learn and understand mathematics.
My problem with the Khan Academy videos is that they are “how-to” videos, and conceptually barren. I recently watched a video on dividing fractions, and the video began with the problem on the screen. He started by saying “Whenever you are dividing any fractions, you just have to remember that dividing by a fraction is the same thing as multiplying by its reciprocal. So this thing is the same thing as three-fifths times … two over one.” This video does not explain why we multiply by the reciprocal when dividing by a fraction, it’s just what we do. There is no development of the topic. I think that students that are told “Do this. Do this. Do this.” will not understand what they are doing, but instead will be able to mimic the video’s work. I don’t think they will retain the knowledge, and we cannot build world-class math students on such a shaky foundation.
Now, don’t get me wrong, I love the Khan Academy videos. But I love them for what they are – how-to videos that students can refer to as they are learning a topic. I send my students to these videos all the time. I love that they are available online for free. I love the story of how he started doing the videos. I especially love how he left his job as a hedge fund analyst to do these videos, there’s something admirable and Escallante-ish in that. I feel badly saying anything negative. It’s just that in their current form they cannot teach students, they can only reinforce what has been already covered in the classroom. They cannot be used to truly teach mathematics.
Am I missing something?
Please leave your opinion as a comment, or you can reach me through the contact page at my web site – georgewoodbury.com. I’d especially like to hear from those of you who have experience in flipping the classroom.
-George
I am a math instructor at College of the Sequoias in Visalia, CA. Each Wednesday I post an article related to General Teaching on my blog. If there’s a particular topic you’d like me to address, or if you have a question or a comment, please let me know. You can reach me through the contact page on my website – http://georgewoodbury.com.
Solving Systems of Linear Equations by Substitution
The first algebraic technique for solving systems of two linear equations in two unknowns is the substitution method. I teach my students to look for one of two scenarios for using substitution:
- One of the equations already has an isolated variable, like or
- One of the equations can be easily manipulated in order to isolate a variable. What we are really looking for here is an equation that has a “plain” x term or a “plain” y term. That is, there is an equation in which the x term or y term has a coefficient of 1 or -1.
(Later I amend this approach to only using substitution when one of the equations already has x or y isolated.)
Example 1
Solve:
Note the second equation: . This equation has isolated on the left side of the equation, and tells us that is the same as , so we can replace in the equation by the expression .
(Substitute for .)
(Distribute.)
(Combine like terms.)
(Subtract 18 from both sides.)
(Divide both sides by -1.)
Now that we have “half” of our solution, we need to find the y-coordinate of the ordered pair by back-substituting 5 for x in either of the original equations. It will usually be more efficient to substitute into the equation that had the other variable isolated.
(Substitute 5 for x.)
(Simplify.)
The solution to this system is .
We can check our solution by substituting 5 for x and 1 for y in the other equation, .
(Substitute 5 for x and 1 for y.)
(Multiply.)
(Subtract.)
The solution checks.
Example 2
Solve:
Note the first equation, has isolated on the left side of the equation, and tells us that can be replaced by in the equation .
(Substitute for .)
(Distribute.)
(Combine like terms.)
(Subtract 30 from both sides.)
(Divide both sides by 11.)
To find the x-coordinate of the ordered pair, substitute 6 for y.
(Substitute 6 for y.)
(Multiply .)
(Simplify.)
The solution to this system is .
We can check our solution by substituting 9 for x and 6 for y in the other equation, .
(Substitute 9 for x and 6 for y.)
(Multiply.)
(Subtract.)
The solution checks.
Summary
I hope that you find this helpful. If you have any questions, or if you have any other topics you are interested in, you can reach me through the contact page at my web site – georgewoodbury.com.
-George
I am a math instructor at College of the Sequoias in Visalia, CA. Each Wednesday I post an article related to General Teaching on my blog. If there’s a particular topic you’d like me to address, or if you have a question or a comment, please let me know. You can reach me through the contact page on my website – http://georgewoodbury.com.
Systems of Linear Equations in Two Variables – Graphing
There are 3 methods for solving systems of two linear equations in two variables: by graphing, the substitution method, and the addition (or elimination) method. Without using technology, the least efficient technique is solving by graphing. Even if a student scales their graph perfectly, if the intersection of the two lines does not occur at a point whose coordinates are integers we cannot determine the exact solution. (Never mind if the student’s graphs are not perfect.) So, why even teach students to solve systems by graphing?
I start to teach systems by graphing because it helps students develop a conceptual understanding of what a solution represents. Suppose we had the following system of equations:
When we graph the line , we are displaying the ordered pairs that are solutions to that equation. When we graph the line , we are displaying the ordered pairs that are solutions to that equation. So, what does the point of intersection represent? This is the one ordered pair that is a solution to both equations. This helps students to understand what the solution of a system of equations represents.
Once we understand how to find the solution of an independent system of equations by graphing, I ask my students if all systems of linear equations will always have one solution. Someone will always ask “What happens if the two lines are parallel?” Since distinct parallel lines do not intersect, my students understand that some systems will have no solution. (We call this type of system an inconsistent system.)
I then ask if there are any other options besides one solution and no solution. Can two lines have more than one point in common? We then figure out that this could happen only if the two lines are identical. Now my students understand the type of system we call a dependent system. By the way, since graphing lines is so fresh in their minds, along with the slope-intercept form of a line, my students have an easier time understanding how to present solutions to a dependent system as an ordered pair of the form (x, mx+b).
Once I am sure that students understand the graphical interpretations associated with these types of systems, I then move on to the substitution method and later to the addition method. But this discussion on solving by graphing is invaluable to student understanding.
By the way, I do not ask students to solve systems by graphing on their exam. I do ask questions like the following:
- Draw two lines that would form an inconsistent system of equations.
- Draw two lines that would form a system whose only solution is (3,8).
- Draw two lines that would form a dependent system of equations.
[Yes, essentially I’m finding out if they can trace a line 🙂 ]
How do you introduce this topic? Do you ignore it? Do you incorporate technology? Please leave a comment, or reach me through the contact page at my web site – georgewoodbury.com.
-George
I am a math instructor at College of the Sequoias in Visalia, CA. If there’s a particular topic you’d like me to address, or if you have a question or a comment, please let me know. You can reach me through the contact page on my website – http://georgewoodbury.com.
Assessing Student Learning Outcomes (SLOs) with MyMathLab
Last Friday I had the chance to sit with some high-quality math instructors at Taft College, discussing how to use MyMathLab to assess Student Learning Outcomes (SLOs) and to generate data. The basis of the discussion was how to use something similar to my SLO Checkpoint Quizzes on a department wide basis.
One way to begin is to create a quiz for each SLO in the course outline. Since MyMathLab will mark each question as correct or incorrect without partial credit, each quiz should be long enough and varied enough so that students who make a “careless error” on one particular problem can still prove mastery on the remaining problems.
One option would be for one instructor to create a series of SLO quizzes and have the rest of the department import those quizzes. Another option would be to create a new MyMathLab course that all of the students can enroll in. (MyMathLab allows students to sign up for other courses that use the same textbook.) The advantage of this new course would be that all of the data would be in one place (no exporting and emailing results by individual faculty). A potential drawback is that the results will not be broken down by individual instructors, but if you are looking for department-wide information that is OK.
When to give the quizzes? I give mine at the end of the semester, but you could give them as the semester progresses.
How many attempts should each student get? I allow my students to take them as many times as they’d like, but you can limit them to as few attempts as you’d like. (In my experience, leaving no limit for attempts encourages students to pursue mastery.)
Data to report? There a lot of ways to go. You can report the average score for each quiz. You can report the percentage of students who achieved a benchmark score. Both of these are quite easy to do in the MyMathLab gradebook, or you could use Item Analysis to drill deeper for results on particular questions/objectives.
If you have any questions about how I use SLO quizzes, or if you’d like to run ideas for your school by me, drop me a line. You can leave a comment, or reach me through the contact page at my web site – georgewoodbury.com.
-George
I am a math instructor at College of the Sequoias in Visalia, CA. Each Monday (during the semester) I post an article related to MyMathLab on my blog. If there’s a particular topic you’d like me to address, or if you have a question or a comment, please let me know. You can reach me through the contact page on my website – http://georgewoodbury.com.
Creating a Community of Learners – TCCTA (1/2011)
-George
I am a math instructor at College of the Sequoias in Visalia, CA. If there’s a particular topic you’d like me to address, or if you have a question or a comment, please let me know. You can reach me through the contact page on my website – http://georgewoodbury.com.
Teaching Linear Inequalities in Two Variables
In Elementary Algebra, I love teaching linear inequalities in two variables at the end of the chapter on graphing lines because it gives me one last chance to go over how to efficiently graph a line. Use the intercepts or use the slope? Is it vertical or horizontal?
It can be a frustrating section for me as well. Some students really have a hard time grasping which half-plane to shade. The way I have always done it:
- Determine if the line is dashed or solid.
- Graph the line using an efficient technique.
- Pick a test point not on the line, preferably the origin (0,0).
- Substitute the coordinates into the original inequality for x and y.
If the inequality is true, then the ordered pair is a solution. Shade the half-plane containing the test point.
If the inequality is false, then the ordered pair is not a solution. Shade the half-plane that does not contain the test point.
Each semester there will be a group that can do everything except figure out which side to shade. It’s frustrating because I think it is pretty clear and straightforward.
Next semester I am changing my approach. Suppose the example is .
- I will have them graph the line, using the intercepts of (6,0) & (0,-4).
- We will then label the line and we will go over the idea that this line represents all of the ordered pairs for which is equal to 12.
- I will explain that this line divides the rectangular plane into two half-planes. One of the half-planes contains points for which and .
- I’ll pick a point below the line to the right, like (6,-5) and substitute the coordinates into the expression , which will result in 27. Since , we will then label that half-plane as .
- I’ll pick the origin, which is above the line to the left, and substitute the coordinates into the expression , which will result in 0. Since , we will then label that half-plane as .
- We will finish by shading the side labeled .
After 2 or 3 examples done this way, I think the students will understand what each half-plane represents and have an easier time determining which half-plane to shade.
How do you introduce this topic? How do you feel about this approach? Please leave a comment, or reach me through the contact page at my web site – georgewoodbury.com.
-George
I am a math instructor at College of the Sequoias in Visalia, CA. If there’s a particular topic you’d like me to address, or if you have a question or a comment, please let me know. You can reach me through the contact page on my website – http://georgewoodbury.com.