So, my idea was this – try to pull together what we know about perpendicular slopes, our developing ideas of vectors as a physical object similar in nature to a line segment, and developing an intuition about the fact that a 90 degree rotation should result in a move of one quadrant in a certain direction. I asked for three coordinates from my students and drew a triangle. I asked them to predict where this triangle would end up after we moved it 90 degrees clockwise. Two of the coordinates given were in quadrant I and one was in quadrant IV. It seemed that my students were happy/comfortable with the idea that the two quadrant I points would live now in quadrant IV and that the quadrant IV point would move to quadrant III. This may have been a tepid agreement in retrospect. Next, I focused our attention on one of the quadrant I coordinates and I drew a segment from the origin to that point. We talked about the slope of the segment, we compared this segment to a vector, we talked about the length of the segment. I then asked the students to imagine a wheel and I told them that when I think about rotations I think about a bicycle wheel. In my mind I saw this segment as a spoke and I thought about distance from the point to the center of the wheel. Here is one place where I know I failed my students. I did not explicitly stop at this point and discuss distance the way I could have/should have. I also have a handful of students who are still struggling terribly with the idea of calculating distance. We have been talking about it since day two, I have coached them to think about Pythagoras, we have practiced it repeatedly. The combination of squaring, of square roots, of subtraction in one piece of ‘the distance formula’ and addition in another piece of it, comfort with mental arithmetic, all of these factors are working against my students being unanimously comfortable with calculating distances. So, the next step in my plan was to ask them what they recalled about perpendicular slopes. They all should know this and most recalled it pretty quickly. We had a segment in front of us with a slope of 4/3 and my students quickly agreed, maybe passively maybe enthusiastically, that a segment perpendicular to this would have a slope of -3/4. So, the question at hand was now whether the fraction was in the form or -3 over +4 or in the form of +3 over -4. I was convinced in advance of this lesson that this string of conversations would be a positive path to take. I felt that the combination of recalling past slope ideas, looking at the physical Cartesian plane, tying in ideas of line equations, etc. would gel together to make a lasting learning experience. I was wrong. When I prodded them toward the conclusion that -3 over +4 was the conclusion we wanted I saw some uncomfortable faces. When I mentioned the idea of a spoke as a visual to hold on to, I saw blank faces at this point. I got a bit frustrated and asked for my students to describe to me what they were thinking of when I mentioned the word spoke. Nothing. I pulled up a google image of a bicycle wheel and asked them to tell me what the spoke was in the image. By this point their reluctance to engage in this conversation was building, my frustration was increasing, and any positive momentum in building this process was falling apart. My fault for showing my frustration. My fault for stacking up too many ideas at once, I think. When I spoke to my Geometry colleague she felt that adding on the layer of talking about perpendicular slopes was the tipping point of discomfort for my students. I trust her instincts on a number of levels in part due to her experience in teaching our Algebra I course. She knows these Algebra kiddos and knows not only what they know but how comfortable they are knowing it. So, at this point it was clear to me that this was slipping away. We limped to the end of the conversation. Most students were willing to agree that the point (4,3) would end up in quadrant IV. They were split on whether it would land on (4,-3) or on (3,-4) and it honestly felt like many were mentally tossing coins to make this call. I showed them the conclusion on GeoGebra and we sort of ran out of time by this point. We have since gone back and tried to reinforce the conclusion we reached and I think that most of my students can reliably answer this question, but I am completely uncomfortable with how we got there. I would love any insight/advice about how to best structure this info. You can certainly drop a comment her or over on twitter where I am @mrdardy

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I asked this class today how they would feel about these two forms of the question. Most of them quickly agreed that they would feel more comfortable answering question B than question A. I followed up by asking whether success on question A might feel more like success and a handful agreed that this probably was true. I am not sure what to make of this informal poll and I am bouncing this idea around in my head. I’d love to hear what you think and push back with some questions about my motivations/hopes in (possibly) restructuring my assessment in this direction.

P.S.

I have been urging them to have GeoGebra open nearby when they do their work so that they can look at graphs and ask for derivatives to verify their own work.

]]>Beginning in the 2017 – 2018 academic year, our math department is adopting a policy of expecting test corrections on all in-class tests. The policy is described below.

- When grading tests initially each question will get one of three point assignments

- Full credit for reasonable support work and correct answer.
- Half-credit for minor mistakes as long as some reasoning is shown.
- Zero credit (in very rare cases) when there is no reasonable support shown or if the question is simply left blank.
- When grading tests, I will not put comments, I will simply mark one of these three ways.
- You will be allowed to turn in corrections. Corrections will be on separate paper and will have written explanations of errors made in addition to the correct work and answer. This work is to be in the student’s words but can be the result of consultation/help. These corrections will always be due at the beginning of the second class meeting day after the assessment is returned. You will return your original test along with your correction notes. I will remind you of this every time I return a graded test to you.
- It is not required that you turn in test corrections.
- The student can earn up to half of the points they missed on each individual problem.
This policy does not apply to quizzes, only to in-class tests.

There are a couple of items in the learning curve to report on here. I will lead with the positives –

- We have an after school conference time that many students take advantage of for extra help. My room has been more crowded this year than it has been for years. I take this as a plus sign that students are committed to seeking help and investing in their math studies. Many of them are there talking with me and with their classmates about test corrections.
- I have had a number of students turn in their corrections the same day that they received their tests. It is a rare thing for students to turn in work days early, it is happening regularly right now.
- I walked out of my classroom today with a new student who was talking excitedly about how she is really thinking carefully about her work and she is sure that she’ll remember material better because of this.
- It is faster to return tests since I am simply marking them 100%, 50%, or 0% for each problem.

Now a few negatives, followed by some philosophical pondering about this whole endeavor.

- I anticipated that there would be very few zero scores on problems. There have been more than I thought but I hope that is a factor of students learning to show some work. This may be a positive as a zero stings a bit and they may be more inclined to be careful in their explications.
- Some students feel stung by relatively minor mistakes that initially result in a 50% on an individual problem. These minor mistakes turn into 75%. I am trying to point out that relatively major mistakes can also end up at the 75% level but some students feel a bit cheated.
- Early in the year averages fluctuate quite a bit anyway, but the fluctuations are exaggerated in this system. I see already that overall averages are a bit higher than normal and there is much less variance in scores. However, some students are scared since they have a hard time seeing the long game as clearly.
- Explaining this to folks outside the department has been a bit of a challenge.

When I was working on my doctorate I had a professor (my thesis advisor) who had a policy that every paper **will** be rewritten, not just every paper **can** be rewritten. The way he did this was to return our first drafts with no comments, just hash marks in the margin at certain points of the paper. These hash marks might be there to point out a flaw in our argument or our paper’s structure. They might also indicate a highlight. They might indicate a misspelling or a simple grammar problem. He was willing to discuss these hash marks in his office hours as long as it was clear that we had sound questions about them, in other words we had to prove to him that we had reflected on our writing. I have never thought so much about my own writing as I did in that class. I do not expect my 14 year olds to do this kind of self analysis, but I know that they ARE capable of careful reflection if they are given the time, space, and motivation to do so. What I am seeing when they come to me is that they have looked over their test, they have referenced notes and their HW. They have done careful thinking and they can usually explain their mistake on their own. This is not universal, but it is happening more often than not. Many students who come to my room to work on corrections have almost no question for me. They are berating themselves for ‘stupid mistakes’, they are laughing at silly things they wrote, they are even saying ‘I have no idea what this work means’ I am pretty convinced that this can be a huge growth opportunity for my students. They are being responsible for their own error analysis here and they are writing thoughtful reflections in the form of ‘On problem 4 I made this mistake, I should have done this instead’

We have midterm grade comments looming and as department chair I know I will have some questions coming my way about our reasoning and the long-term impact on grades. I will try to steer the conversations to long-term impact on learning and self-sufficiency. So far the policy has exceeded my hopes in my classes. I will be checking in with my department to get other points of view soon and I plan on sharing some of those conversations as well.

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I just graded my first problem set from my AP Calculus BC wizards. One of the questions asked for the point on the curve y = x^(1/2) that was closest to the point (4,0). Everyone correctly identified x = 3.5 as the critical x value and about half of them identified (3.5)^(1/2) or sqrt(3.5) [my LaTex skills are weak and I am in a bit of a hurry…] as their y-coordinate. However, about half of them gave me a three decimal approximation. For reasons I cannot completely justify it makes me nutty to see a less exact answer written as an extra step in their work. I know that their science teacher is not interested in radicals in their answers. I know that carpenters do not have radicals on their measuring tapes. I also know that all of my Calc BC kiddos had the exact value for y written at one point in their solutions and many chose to do a little extra writing to make their answer less exact. Am I being a crank if I make this a point of conversation? Along the same lines, I urge them not to rationalize but many cannot help themselves. I urge them to leave a line equation in point-slope form when that is one of the steps in their problem-solving process. I ask them to write x < 3 rather that 3 > x, especially in a piecewise function where I want to read through their domain in order.

These are tiny, tiny problems to focus on. I recognize this. But I also know that I will spend many months with this group of students and I want them to understand my thoughts since I am asking them to routinely explain theirs on paper to me. I would love to hear points of view about how important any of these habits are for kids of this caliber. I am completely open to recognizing that these are just weird little quirks of mine, but I also hope that there is some mathematical logic underlying all of this. Please drop a line to let me know what you think and how you have responded to students in your efforts to help them develop a clear and consistent strategy for communicating their mathematical ideas.

]]>First, I should remind everyone reading this what our new policy statement is. Here is what my students read on their syllabus this year.

Beginning in the 2017 – 2018 academic year, the math department is adopting a policy of expecting test corrections on all in-class tests. The policy is described below.

- When grading tests initially each question will get one of three point assignments

- Full credit for reasonable support work and correct answer.
- Half-credit for minor mistakes as long as some reasoning is shown.
- Zero credit (in very rare cases) when there is no reasonable support shown or if the question is simply left blank.
- When grading tests, I will not put comments, I will simply mark one of these three ways.
- You will be allowed to turn in corrections. Corrections will be on separate paper and will have written explanations of errors made in addition to the correct work and answer. This work is to be in the student’s words but can be the result of consultation/help. These corrections will always be due at the beginning of the second class meeting day after the assessment is returned. You will return your original test along with your correction notes. I will remind you of this every time I return a graded test to you.
- It is not required that you turn in test corrections.
- The student can earn up to half of the points they missed on each individual problem.
This policy does not apply to quizzes, only to in-class tests.

The first class to have a test this year was my AP Calculus BC class. This class has sixteen students of the highest math caliber at our school. They had a test in class on Tuesday and on Tuesday night I marked those tests. On a number of occasions I had to restrain myself from circling something or writing a note to a student. I went through and only marked each question as a 0, a 5 or a 10. There were six questions, so I graded 96 questions overall. Only one 0 out of all these 96 questions. Thirty four questions earned half credit and the other sixty one questions earned full credit. Of those thirty four, most mistakes were minor and in the past they would certainly not have suffered a five point penalty, but in the past they would not have had the ability to earn back points and they would not have had the motivation to think clearly about what happened. Due to quirks in our rotating schedule, the second class day after yesterday is not until Monday. However, I have six of my students in my room after school yesterday working on corrections. All of them spoke to me about problems and three of them were working with each other. Four of the six students there completed their corrections and turned them in already. This feels like success. I know that it is early in the year and students have a little more energy right now. I know that this is my most motivated (by knowledge, by interest level, and by grades) group of my four different class preps I have this year so I will not expect quite this level of engagement right away. Oh yeah, two of the students there yesterday only missed points on one of the six questions. The could have happily taken their 92% and gone home to worry about other work instead. I expect that I will see another one or two folks today and then get a slew of corrections in on Monday. The initial grading was a little bit faster and I could get them their tests back right away. Looking at the corrections will take a little time, but this is time I want to take and it is encouraging the kids to think about what mistakes they have made and (hopefully) not make those same mistakes again. I’ll keep updating on this experiment.

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Here is the problem –

Doris enters a 100-mile long bike race. The first 50 miles are along slow dirt roads, while the second half of the race is on smooth roads. Assume that Doris is able to travel at a constant rate of speed on each surface.

- If Doris’ speed on the first 50 miles of the race is 10 miles per hour, what must be her speed during the second half of the trip so that her average speed over the whole trip is 13 1/3 miles per hour?
- If Doris’ speed on the first 50 miles is12.5 miles per hour, what must be her speed on the second half of the trip so that her average speed over the whole 100 miles is 25 miles per hour?

A fairly standard question and I admit I stole it directly from a text I use ( a pretty cool Differential Calculus book for my non-AP class) and I originally intended to just use it with my Calculus Honors class this morning. After the discussion with them, I decided it was worthy of the attention of my Geometry section and my Discrete Math class as well. It is kind of fascinating to me to think about the different receptions that the problem had in each class. In all three classes I asked them to think about the first question and wait until we discussed it before moving on. I KNEW what mistake was going to be made. There was no doubt in my mind that the answer to question 1 would be 16 2/3 and the students did not disappoint me. They focused on the information given and processed it in a logical way given their use of the word average when considering two measurements. What they did not focus on was time and it is logical that they did not *because it is not explicitly mentioned in the problem at all*. My hope going in with my Calc Honors kiddos was that this would be an object lesson in weighted averages. What it turned into in my other two classes was a bit of a primer in how to think through a word problem instead of just automatically applying some mathematical operation on a set of numbers in front of you. In each class after the initial incorrect solution was offered I presented the following question. “I have a 90 on my first test and I score 100 on my second. What is my average? Now, I have a 90 average after four tests and I score 100 on my fifth. Is my average the same in each situation?” I had hoped, overoptimistically, that this would prompt thought about time but in all three classes I ended up explicitly urging them to think about time. In Calculus Honors and in Discrete this led most (maybe all) students to a correct conclusion. Not so with my younger Geometry students who were still a bit wary of the problem. In fact, one student asked me if all of my questions were going to be like this. I need to be a little more careful about these last minute decisions to follow my muse and approach a problem. I need to be more thoughtful about how appropriate the question is for the audience at hand. I still believe that this is a meaningful question for my Geometry kiddos to wrestle with, but perhaps I would have served them better by not making this the opening question on the second day of school…

Both groups of older kids arrived at the correct conclusion to the second question and they were amused by the result. Only two days in but of the eight classes I have had, I’d say 7 were successful with one uncomfortable miss.

]]>I mentioned over on twitter that I had the great pleasure of taking on a gig as a DJ at a local college radio station this summer. My wife works at a college across the river from where I work and she helped me land this fun gig. I just got the good news that I can keep my slot at least through the fall. I will be on (as DJ Calc – an old in-joke from my past) on Thursdays from 4 – 6 PM ET on wrkc.kings.edu where you can stream and listen online if you are so inclined.

One of the takeaways of the workshop my team did with Henri Picciotto (@hpicciotto) last spring was that we committed to a new policy of test corrections in our department. I teach four different courses this year, three of them are senior and junior heavy while one is freshman and sophomore heavy. They will all receive the statement below with only one tweak. My Geometry kiddos will turn in test corrections on the third class day after receiving their test while the others (Discrete Math, Honors Calculus and AP Calculus BC) will turn theirs in on the second class day. Here is the statement I crafted for a syllabus.

**Test Corrections**

Beginning in the 2017 – 2018 academic year, the math department is adopting a policy of expecting test corrections on all in-class tests. The policy is described below.

- When grading tests initially each question will get one of three point assignments
- Full credit for reasonable support work and correct answer.
- Half-credit for minor mistakes as long as some reasoning is shown.
- Zero credit (in very rare cases) when there is no reasonable support shown or if the question is simply left blank.

- When grading tests, I will not put comments, I will simply mark one of these three ways.
- You will be allowed to turn in corrections. Corrections will be on separate paper and will have written explanations of errors made in addition to the correct work and answer. This work is to be in the student’s words but can be the result of consultation/help. These corrections will always be due at the beginning of the second class meeting day after the assessment is returned. You will return your original test along with your correction notes. I will remind you of this every time I return a graded test to you.
- It is not required that you turn in test corrections.
- The student can earn up to half of the points they missed on each individual problem.
**This policy does not apply to quizzes, only to in-class tests.**

I will definitely be blogging throughout the year about this topic and I’ll be sharing my thoughts and experiences about this change in approach. The baseline message that I hope we will be sending is this : I want you to learn the material at hand and I want you to have an opportunity to show me (and yourself!) that you **have** learned this material.

The last thing that I am thrilled about is our new schedule. After being here seven years and meeting every class on every school day in the same order for the same amount of time we area adopting a very different new schedule. We are moving to a seven-day rotation schedule. We will meet five classes per day and each class meets five times during a seven day rotation. During that rotation each class meets in each of the time slots AND each class has one 90 minute block and four 50 minute class meetings. I am excited on a number of levels about this initiative. I have taught at two other schools with rotating schedules and I noticed a couple of clear advantages. You know that sleepy kid in your 8 AM class? That kids is not usually so sleepy for an 11 AM or a 2 PM class. You know that athlete who keeps missing your 2 PM class because of travel obligations tot he team? That athlete is rarely traveling at 8 AM or 11 AM. You know that class that wanders in right after lunch with a mixture of twitchiness because they do not want to sit again or lethargy as they digest their lunch? You do not see them in the same state everyday. I have seen that different students emerge as classroom leaders at different times of day. Most importantly, I have noticed that students (many of them, at least) give a more honest commitment to effort on HW when they are getting ready for four academic classes in a day instead of six of them. This, too, will be a regular topic of conversation in my blog this year.

As always, drop me a line here or on twitter where I am @mrdardy

I’d love to hear from those who have experienced a major change in school schedules I want to have some idea of how to anticipate possible problems this year. I’d also appreciate any comments about our test correction policy. Anecdotes from experience will probably help me and my team as we make this transition.

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Back? Good.

Alright, let me share a couple of reflections first. Joe is one of the many delightful folks whose acquaintance I would not have made if I had not taken the plunge into this online world of collaboration. He and I met in person in Minneapolis and had a really in depth conversation about parenting, especially with regard to tech use for children. His words have echoed in my ear this year and my wife and I took on the challenge of a smart phone for our 14 year old. My son does not know it but Joe is one of the reasons why I was able to sort out my protests and come to the decision to give him one. So, in addition to my life being improved by Joe’s friendship, my son’s life is improved by Joe’s wisdom. Anyways… This summer I got to spend time with Joe again at meals (especially a LOVELY dinner at the oddly named Cowfish) and at a session run by David Butler (@DavidKButlerUofA) called 100 Factorial. As Joe wrote, he and I were in a group of four with Jasmine Walker (@jaz_math) and Mauren (Mo) Ferger (@Ferger314) We worked on a problem called skyscrapers (you can find a cool online link here ) and we were all full engaged. Now, I knew jasmine and Joe already and knew Joe was a primary teacher. This fact did not cross my mind during the time we were working on the problem, but it sounds like maybe it did for Joe based on his blog post. That evening about a dozen folks all descended on Cowfish for dinner and I was sitting near Joe and Jasmine. I won’t repeat the story of our conversation, Joe covered it well. What I do want to do is think out loud about my perception of the conversation and try to get into Joe’s head a little bit as well as getting into my own head. Early in the conversation I mentioned to Jasmine that I had the impression that she might be ‘mathier’ than I am. I tend to be a little self deprecating in this area, I have three degrees and they are all from College of Education. I have no formal math degree but I took a load of math classes in college and have taught a load of them in my 30 years of teaching. I know a few things and I am pretty quick at making connections, if I do say so myself. However, I also know that I am TOO quick to make certain conclusions and this caused some trouble in the Skyscraper game and I am also a bit too quick to throw in the towel if I don’t see at least some sort of pathway pretty quickly. I don’t need to know an answer right away but I do need to have some sense of where to find the answer to help me be persistent. As Jasmine and I were trying to ‘un’ one-up each other (Edmund Harriss (@Gelada) was sitting next to me and he joked that this was the opposite of a pissing contest) I was also wrestling with the question Joe had out on the table comparing the Exeter problem sets with the puzzle we played with that afternoon. Looking back, I fear that the banter with Jasmine about who was less ‘mathy’ may have been somewhat hurtful now that I see the feelings Joe laid out in his blog. If that is true, I am deeply sorry. What I DO remember distinctly about the conversation was that I described different initial reactions to the lovely problem sets and the creative puzzles that Prof Butler laid out. In the problem sets there is a reassuring (or distressing, I guess) sense that these are MATH problems. That there is some MATH technique or formula that will be needed to nudge me down the road to success. With the Skyscraper problem, it was clear to me that this was an exercise in LOGIC. MATH thinking strategies certainly are handy and helpful, but this problem did not yield to an algorithm (or if it does, I am not nearly clever enough to know it) but it did yield to persistence and communication. Joe talks about wanting to overcome some old residual fear or discomfort to go ‘play with the big kids’ on the Exeter problem sets. What I hope he recognizes is that he WAS playing on that stage, it was just in the cafeteria with Skyscrapers instead. I have had conversations around Exeter problem sets with students and with other teachers. They have been great conversations but they were certainly not more memorable than the feeling of diving in and and conquering the Skyscraper problem. Joe was an integral part of that problem-solving team and he caught a couple of my mistakes when I jumped to quick conclusions. We are all on a continuum of comfort and confidence in different problem solving scenarios and Joe’s thoughtful and honest blog post serves as an important reminder to me to try and be more aware of these feelings in others as a new school year begins.

Joe told us this summer that he has retired from his daily gig and is now doing a variety of consulting jobs. He talked about how some folks collect baseball stadiums over the years, visiting ballparks around the country. He talked about the idea of doing that with classroom visits now that he has a more open calendar. I would LOVE it if he carries through with this plan, it would be great to hear his perspective. I would welcome him to my school with open arms but I would also be slightly anxious and a bit nervous about it. Would I still seem like ‘one of the big kids’ if he saw me in action? This kind of anxiety, I think, is probably a good thing for me. It keeps me on my toes. I want to make sure that my students have a meaningful experience in my classroom and one of the ways I can do that better is to imagine that I was also crafting an experience for someone like Joe.

]]>Note that our first day has 25 minute classes and a long community gathering.

In Geometry I have started the past three years with a dramatic introduction to the handshake problem. It generates some fun guessing and conversations right off the bat. We are also able to revisit this problem in various forms during the year. I think it is a winning first day activity.

In our Calc Honors class I will take students out in the hallway with some wheels chairs. I will have a segment of hallway measured for length and we will have some races pushing these chairs down the hall. This, I hope, will generate some conversations about average speed tat we CAN calculate and all sorts of instantaneous information that we cannot. This should be a basis for distinguishing between secant and tangents over the first days/weeks of the course. Plus, it is fun to run down the hall!

In Discrete I am going to use a fantastic quote that I read this summer (you can find it here ) I think that this might generate some fun research and some fun conversations about magnitude.

In Calculus BC I want to start with a deep dive into a conversation about linearization and approximations. I have gathered some fun ideas on twitter about how this conversation can unfold. I hope it leads to quite a bit of noticing and wondering about accuracy and when/why that accuracy falls apart.

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I was SO flattered to be asked to do this and it was such a blast to chat with these four lovely and brilliant people. I told John on Sunday that I was jealous of his students. My apologies for having this wonderful experience slip my mind when I posted earlier today.

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