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hay baler problem from IMPI've just this moment noticed the 'hay baler problem' Barry posted on his page.Here's a problem that appears in IMP for 9th grade It is known as the "Haybaler Problem" “You have five bales of hay. For some reason, instead of being weighed individually, they were weighed in all possible combinations of two: bales 1 and 2, bales 1 and 3, bales 1 and 4, bales 1 and 5, bales 2 and 3, bales 2 and 4 and so on. The weights of each of these combinations were written down and arranged in numerical order, without keeping track of which weight matched which pair of bales. The weights in kilograms were 80, 82, 83, 84, 85, 86, 87, 88, 90 and 91. Find out how much each bale weighs. In particular, you should determine if there is more than one possible set of weights, and explain how you know.” David Klein, a mathematics professor at California State University at Northridge comments on the problem. “The process of solving this problem made me resentful of the stupidity and pointlessness of it. There is nothing ‘real world’ about it. It is completely inappropriate for kids who likely have not been taught how to solve simultaneous linear equations, or exposed at most to two equations in two unknowns. If I had been given such problems at that age, I think that I would have hated math.” Consistent with much of the philosophy of “real life math”, the goal of the exercise is to explore strategies and to be able to write about it. This is made apparent by the “student guide” that accompanies the problem. It is essentially a scoring sheet, containing categories, with points awarded for each, such as “Restate the problem in your own words” (4 points); describe all the methods you tried before reaching your solution(s) (4 points); describe the process that lead to your solution(s) (4 points); describe all assistance provided and how it helped you (2 points); state the solution (2 points); describe why your solution(s) is correct, include all supporting data (6 points). Out of a total of 50 points, only 2 are given for the solution. In fact more points are given for describing why the solution is correct. It's unbelievable. You really do have to see this stuff in the flesh to know what our kids are up against. On the other hand, I'd bet money there are no more than 5 teachers on the planet willing to use the IMP grading rubric, (pdf file) if that. I've been a teacher myself; I've used grading rubrics (teaching freshman rhetoric at the University of Iowa). The IMP rubric asks the teacher to use 18 separate categories for a total of 50 points to score one problem. Unless the NCTM is now allowed to send federal auditors into the classroom (which is pretty much what we've got in Manhattan at this point) that's not going to happen. Students can earn a grand total of 2 points, out of 50, for the right answer. No teacher's going to go along with that. updateCheck out the IMP web site.
"IMP™ Receives Award from the U.S. Department of Education"Here's the Mathematically Correct review. (pdf file) Back to main page. CommentsAfter entering a comment, users can login anonymously as KtmGuest (password: guest) when prompted.Please consider registering as a regular user. Look here for syntax help. Plus the fact that it's a bad problem. Students haven't been taught the linear algebra necessary to solve it. It's not the type of problem that generalizes into a class of problems and which can serve as a foundation for more complex ones. It stands as a "top down" approach in which in the paraphrased words of NCTM: Understanding is the foundation upon which skills are then learned. -- BarryGarelick - 01 Jul 2005 I have to say: just reading through the problem I have no idea how to solve it using conventional high school algebra. Doesn't it have a gazillion variables? Can it be solved using high school-level algebra? I've been noticing lots of problems where you have to list endless arrays of 'combinations'--that must go along with the idea that in addition to always having more than one way to solve a problem, many or most problems have more than one answer, too. -- CatherineJohnson - 01 Jul 2005 You know, the word 'abuse' really does jump into my mind, reading this problem. I've restrained myself from saying this so far, but I have frequently felt, listening to the problems in the grade 6 phase 4 class, that the class is 'abusive.' I have thought and said that word. The kids are suffering. These are 6th graders crying at night because they can't do their math and they got a 60 on the last test. Their parents are being told they 'don't belong' in advanced math, that the course is only for the most gifted students. It's c***. -- CatherineJohnson - 01 Jul 2005 Absolutely right. It is abuse. I talked about that very word with Sandy Sstotsky and others in talking through the op-ed that I'll write some day (!!). They agreed with me that abuse is correct, but it carries too much baggage (e.g., Michael Jackson, priests convicted as pedophiles, etc), plus it connotes that teachers are the abusers and that's unfair. Teachers are stuck with these wretched programs. So we've settled on "educational malpractice" which has opened up a very rich avenue of inquiry indeed. As for the haybaler problem, it requires some knowledge of combinatorics and linear equations, neither of which students would have had in the 9th grade. Not to mention the fact that no farmer in his right mind would ever weigh bales of hay that way, bringing into question of how "real life" is this piece of c***? David Klein solved it and explained it to me and there is one solution. But as he says, had he been forced to do it in the 9th grade, he would have hated math. -- BarryGarelick - 02 Jul 2005 They agreed with me that abuse is correct, but it carries too much baggage (e.g., Michael Jackson, priests convicted as pedophiles, etc) Definitely. Still, educational malpractice wouldn't describe the situation I've seen, 'from afar,' in the 6th grade math class this year. The problem there isn't a constructivist text, btw. They use Prentice-Hall. But they have a constructivist attitude. -- CatherineJohnson - 02 Jul 2005 My dad was a farmer. Definitely, no one in the entire Middle West ever constructed such a table. I probably don't know what combinatories are. As I say, we're going to have a full month's worth of these problems thrown at us next September, if the course is not radically reformed over the summer. My plan is to have Carolyn solve them while we carry on learning math around here. (Hi Carolyn!) -- CatherineJohnson - 02 Jul 2005 Barry, do you have any thoughts on Kumon Math? Robert Talbert thinks it's probably good. -- CatherineJohnson - 02 Jul 2005 Hi Catherine! Now I know your nefarious plans for me. -- CarolynJohnston - 02 Jul 2005 Since we are on the subject of educational malpractice, I want your comment on a particular situation. The first student I tutored is now going to be a senior in high school. When she was in middle school, she got a D in pre algebra in the 8th grade. Her mother was worried about how she would do in algebra, so I tutored her over the summer. Very typically, we had to go back to fractions and teach middle school math. But she got it and did fine in algebra and geometry. This year, she had Algebra II. She was getting an A until the final, then she got a 60. The teacher won't show her the final because she gives the same one every year. So she doesn't know if her problem was the material or some accuracy errors. But here is the real issue: the teacher recommends that she take precalculus next year, not calculus. She want to major in some type of science in college. I say she needs to take straight calculus. If she passed all her other classes, she should be ready. All the kids that she will be competing against for college entrance will have at least calculus on their transcripts. But I think the teacher has her convinced that she can't do it. What do you think? -- AnneDwyer - 02 Jul 2005 The teacher should show her (and her parents) the final. This sounds fishy to me. I can see not wanting to hand out copies, but she should be able to see her final in a meeting with the teacher. The best thing to do would be to get hold of an assessment test. Hmm... I wonder if there is a final assessment for precalculus math in the set that David Klein drew up for California... I'm going to check it out. -- CarolynJohnston - 02 Jul 2005 No, those only go up to 8th grade. But here is a link to an assessment test specifically for placement in AP Calculus AB, which is the AP class that she'd most likely take (the other is AP Calculus BC, and I don't think most schools offer both). -- CarolynJohnston - 02 Jul 2005 As usual, someone on this site always manages to come up with exactly what I need. I pulled off the assessment test. It will make an excellent review for me also. Then, using the test, we can make an informed decision about whether she is ready for calculus. Thanks again!! -- AnneDwyer - 02 Jul 2005 I think Carolyn's advice is exactly right:
I've got to corral John to come help us out here. John & my friend Lissa. -- CatherineJohnson - 02 Jul 2005 Overall, I liked the assessment test. It was very heavy on calculation and very light on word problems, but it is only meant to determine if a student has enough skills to take calculus. But, in general, I don't think an assessment test should be multiple choice. It is hard to tell whether the student can do the whole problem or just enough to guess at the right answer. When I give my tutoring clients an assessment test, I give them mostly calculation problems. I usually give four word problems: one problem is slightly below what they should be able to do. It is easy to read and very straight forward. One problem is at their grade level. It uses straight foward numbers but is multistep. If they are above 3rd grade but still in elementary school, the third word problem involves fractions. It is usually a problem from Singapore math that has several steps clearly deliniated with an a, b, and c. They should be able to get at least part of the problem. The fourth problem is a multistep problem that requires that the student have some logical way (ie bar model or equations) of keeping everything straight. -- AnneDwyer - 04 Jul 2005
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