Tag Archives: Homework

Beautiful Problem Solving and Odds and Ends

While most of my colleagues enjoyed a well-deserved day off in honor of Martin Luther King, Jr. we were at work here in our boarding school. We take advantage of these days as visitation days and we keep on counting the days of the year.

Last week I wrote about my frustrations with trying to find a way to help keep my students more aware of the benefits of daily practice in Geometry. This weekend I engaged in a lengthy and mind opening twitter conversation with Elizabeth (@cheesemonkeySF) and my mind is still buzzing with ideas. I noticed something today that I may be able to take advantage of. Tomorrow we have our next Geometry test. This is the second year that my school is using the Geometry text that I wrote. This means that we are still working our way through the strengths/weaknesses of the text and we have a storehouse of documents to draw upon. I decided earlier in the year that I would hand out last year’s tests as practice a few days before this year’s test over similar material. So, last Friday I gave a copy of the test from last year that covers through Chapter Six of our text. Today in class I saw more evidence than usual of HW completion. So, when the HW feels particularly helpful then my students are more likely to complete it. Pretty logical, right? What I need to do then is to make sure that I can get buy-in like this more frequently. I have a batch of quizzes from last year that I can easily give out mid chapter as weekend HW that both serves as a sneak preview of the kind of quiz questions I was interested in asking last year AND serves as good, focused practice that feels to my students as if it has more payoff. This will not solve all of the problems I have been wrestling with and I need to sort out Elizabeth’s sage advice and figure out how to incorporate it in a way that fits me, but this feels like progress. I am happier about Geometry than I was last week and I am optimistic about tomorrow’s test. I hope that I will be able to report on student success.

Last week I also wrote about a problem posed to me by an alum when he was visiting. I may not have reported the problem accurately, so here is a second take. One hundred people are lined up to board an airplane with 100 seats. Each person has one seat assigned. The first person boards the plane and randomly chooses a seat. After that, each person who boards will sit in his/her assigned seat if it is available. If the correct seat is not available then that person will randomly choose a seat. What is the probability that the 100th person will be able to sit in the correctly assigned seat? I broke this problem down after one of our boarding community dinners last Thursday and a colleague and I simplified it to two people (50% chance, no surprise!) and then three people. With three people – call them A, B, and C – the seating arrangements are ABC, ACB, BAC, BCA, CAB, CBA. Two of these arrangements have C sitting in the third seat and for the purposes of this permutation, I am treating that as the ‘correct’ seat. However, the arrangements ACB and BCA are not possible under these rules. If person A does not sit in seat B, then person B is obliged to sit in his correct seat. So we have two of four possibilities for a 50% success. This seems pretty suspicious and I try to sort out the arrangements with four people. I won’t bore you with the detail but this is also 50%. When I mentioned this problem to a number of colleagues one of them mentioned that her son had talked about this problem from a math competition. Her son is in my AP Calculus BC course and he is an extraordinarily talented mathematician. He explained the problem this way in class today and I probably will not be as elegant as he was. Here is his take:

By the time that person two sits down on the plane we know that his seat has a person in it. Either it is person one and then person two chooses another seat or his seat was available and he sat in it. Similarly, by the time person three sits down we know that someone is in person three’s seat. Either person one or person two is accidentally in that seat or person three sits in her proper seat according to the rules of this problem. We can extend this argument all the way to person ninety-nine. Now, we know for a fact that all seats from person two’s seat through person ninety-nine’s seat are all occupied. The only mystery is whether the other occupied seat is the first person’s seat or the hundredth person’s seat. It is not a stretch to see that these two possibilities should be equally likely.

What I LOVE about this explanation is that it does not rely on combinatoric wizardry or thorny algebra manipulations. It also make crystal clear sense once it has been explained but it did not make crystal clear sense before that. It seemed completely unreasonable to me that, with so many people involved, the answer would be so clean. In fact, my student’s explanation made it clear that the number of people on board is a complete red herring. It might as well be one thousand people instead.

While I might have enjoyed the day off, I also enjoyed the day on.

Geometry Progress Report

I have a couple of posts that I want to make. It might be a busy weekend between writing midterm comments and airing my thoughts here. I promised to report back on my grand experiment with lagging HW. Now that we are three weeks into the term I think that I have some meaningful observations.

My first observation is that I need to find some meaningful way to regularly incorporate HW so that my students feel that it is a meaningful exercise. I think I am making strides by writing problem sets that reflect my book and our class conversations. I think that I have written problem sets that strike a decent balance between practice and challenge problems. I have been making class space for conversations about the current topics and trying to create some space for simple practice and check-in with some entrance slips. However, it is becoming pretty apparent to me that too many of my students are not in the habit of doing their HW on a daily basis. When we check in on HW at the beginning of class there are plenty of empty desktops and too much silence. It also seems clear to me that these are old habits and the reason I say that is that MANY of the problems they are struggling with now are related to writing line equations. Since we are juggling perpendicular bisectors of triangles, altitudes of triangles, medians of triangles, and angle bisectors it is kind of essential to be able to work with line equations. I know that these are skills that they have had and have displayed, but if the practice was not put in originally, those skills do not settle in and stick very well. I am reluctant to grade HW for a number of reasons. If all I am doing is checking for completion, then I feel I will be often rewarding sloppy and incorrect work and possibly helping some bad habits settle in. If I collect and grade it based on correctness I fear that I will be encouraging students to take some dishonest shortcuts. Instead, I am trying to use the entrance/exit slip idea to encourage attention during class with the hopes that that attention and the reminders of the skills necessary through the entrance/exit slips will (a) make the HW easier when it rolls around about three days after the class discussion and (b) allow me (and my students) to realize what they do or do not know.

My second observation is that this idea of HW lagging behind instruction will take some time for my students to get used to. They have been SO accustomed to trying their hand at something as soon as they begin to think about it and this new pace feels very different to them. I think that the old habits are working against them as they have expressed more confusion on some of the problem sets than I saw last year when I was using these HW assignments and assigning them the night that we introduced ideas in class. This, again. is something I need to address. I need to figure out how to help coach my kiddos to be able to deal with this process. I am too convinced that this is the right way to do this. Reading about it, thinking about it, I am sure that this is the right thing to do. My first time checking in on their progress right now (on this quiz on Tuesday) was a bit of a disaster. There were a number of scores hovering around 50% and for each of those students I returned the quiz with a practice assignment on writing line equations. I am trying to be positive and emphasizing that they know how to do this. I am convinced that this is true but I saw SO many mistakes on the quiz that it was a bit disheartening.

 

Conclusions? As I mentioned, I am convinced that this is a good way to weave in review, encourage reflection, and try to embed knowledge more deeply. I just need to figure out how to help coach my students so that they can realize the growth that I want to see for them.

Getting Back to Business

So, our school works on a trimester system with Thanksgiving Break (a full week) marking the end of the fall term. We also have fall term finals, so my last full day of classes was November 12. I set myself some lofty goals for the break and met about 80% of those goals. My number one goal, by far, was to do what I could to plan out our next fourteen days for all three of my preps. We have fourteen days of class until the long winter break begins.

I found out late in the summer that I was teaching a new course (around August 10) and I also have two brand new colleagues in my  department. I have not been able to spend as much time mentoring them as I had planned to. The combination of this disappointment, along with perpetually being only a few days ahead of my Discrete class made the fall term a pretty stressful one. I have three preps, five sections, and my chair responsibilities. Luckily, I have a pretty light student load this year.

So, I have my calendar mapped out for Geometry and AP Calculus BC and I have about ten of the fourteen days of Discrete taken care of. Overall I am pretty pleased. Add in the naps and the time with my wife and kiddos and it has been a good break with just enough productivity thrown in.

I am starting off my Geometry kiddos with a three day workshop on Reasoning and Proof. I found this somewhere on the inter webs recently but I cannot recall where. You can find the link here and if you recognize it, please let me know. I am pretty excited about this. I think that it will be a lively way to restart my classes and I am optimistic that the students may make some inroads into understanding the logical structure of proofs. We had a great activity with making peanut butter and jelly instructions for each other earlier in the year. I think that this serves as a nice follow up and I am happy that there is such time between them. My optimistic hope is that the students will make that connection on their own without me pointing it out. This unit has a similar idea with sentence strips outlining the process of making spaghetti. I do know that when I do the PBJ activity again in the future I will scaffold it a little more carefully in advance so that more of the students will have a solid idea how to approach that. If you want to read about our PBJ adventures you can look at this post or this one.

I am also already committed to a project for my winter break. Right before Thanksgiving I engaged in a lengthy and lively twitter discussion with Henry Picciotto (@hpicciotto), Elizabeth (@cheesemonkeysf), Peg Cagle (@pegcagle), Julie Reulbach (@jreulbach), Mattie B (@stoodle), and Chris Baldus (@Chrisbaldus04) We were discussing HW strategies. When to preview ideas, when to lag and let ideas catch up, how to possibly blend those strategies. It was an amazing conversation with people from all around and at least two of whom I am certain that I have never met. One of those great examples of why engaging with twitter has improved my practice. So, I am too weary to rewrite my HW sets that I wrote last year when we rolled out the Geometry text I wrote. But, I realize that the time before January will allow me to write a few more sets that I can use as buffers near the beginning of the year while I let ideas settle in and percolate for my students. The assignments that they would have been working on the night they were introduced to an idea will now come three or four days later. In the interim we will concentrate on in class discussion and practice and I will write some homework sets that concentrate more on helping to cement definitions and some new mechanical skills along the way – along with reminding them of highlights from 2015. I am excited to do this and I would not have had the motivation to do so without the urging of those virtual colleagues who took the time and care to share with me their ideas and experiences. I am a little anxious because change = bad for too many of my students, but I am convinced that the time off will allow me to think deeply about how to be as intentional and clear as possible with my students. The other fear I had and came to grips with is this – I am one of four Geometry teachers at our school. I am also the chair of the department and the author of the text. My ego keeps creeping in and wanting everyone to follow my lead because of both of my roles here. I came to peace (thanks Julie and Elizabeth!) with the idea that I do not have to have everyone on the same page AND with the idea that I can be a better leader in this process next year if I go through it myself this year. I will still share out my old (and new!) pacing guides and homework assignments. I will simply make it as clear as possible that not everyone needs to agree with this HW strategy and with the timing of assessments that this will entail. If the students are not doing homework concentrating on, say, section 6.4 until three days after we introduce that section in class, they cannot be held responsible for that material on an assessment until they have had time to practice. Consequently, assessments will lag behind where we are in class as well. I need to rethink my ideas about what review days mean and look like, but this kind of rethinking is one of the things that makes this job such a joy.