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This Chinese Math Problem Has No Answer. Perhaps, It Has a Lot of Them. (washingtonpost.com)

Fifth-graders in China's Shunqing district were recently asked to answer this question: "If a ship had 26 sheep and 10 goats on board, how old is the ship's captain?" The Washington Post: The apparently unsolvable question sparked a debate over the merits of the Chinese education system and the value it places on the memorization of information over the importance of developing critical thinking skills. "Some surveys show that primary school students in our country lack a sense of critical awareness in regard to mathematics," a statement by the Shunqing Education Department posted Jan. 26 reportedly said. One student offered a pragmatic law-abiding answer: "The captain is at least 18 because he has to be an adult to drive the ship." Meanwhile on Twitter, some have gone with 42, a reference to the science fiction novel "A Hitchhiker's Guide to the Galaxy," by Douglas Adams, in which 42 is the "Answer to the Ultimate Question of Life, The Universe, and Everything." BBC: "If a school had 26 teachers, 10 of which weren't thinking, how old is the principal?" another asked. Some however, defended the school -- which has not been named -- saying the question promoted critical thinking. "The whole point of it is to make the students think. It's done that," one person commented. "This question forces children to explain their thinking and gives them space to be creative. We should have more questions like this," another said.

21 of 443 comments (clear)

  1. How was this question graded? by klingens · · Score: 4, Insightful

    If the question has no answer and is supposed to foster critical or creative thinking, how did the teachers grade the answers?
    What were the actual answers? As it stands, this is bullshit "news" cause the important part of the whole incident wasn't reported. Why am I not surprised that it's "news" from Jeff Bezos' Blog?

    Did the pupils get full credit when they pointed out how the question is unanswerable? Did they get credit for the lower bound of 18? Did they get no credit for things like the 42 answer which is simply a lame old joke?

    1. Re:How was this question graded? by ShanghaiBill · · Score: 4, Insightful

      The correct answer is: Méiyou zúgòu de xìnxi. (There is not enough information).

      I used to live in Shanghai, and my (American) kids attended public schools there for several years. I was appalled at how much the math classes were based on drill, drill, drill with very little actual thinking. I am glad to see some "fuzzy" problems included.

      There are some good things about Chinese math. For instance, in America teachers say "Show your work". In China, the teachers say "Do the math in your head, and only write down the answer". The teacher will call on kids to solve a problem written on the whiteboard, and make them do it with their hands behind their back. My kids can easily add up a column of numbers in their head, so when we eat at a restaurant, I always ask them to check the bill.

    2. Re:How was this question graded? by crunchygranola · · Score: 4, Insightful

      For instance, in America teachers say "Show your work".

      This was my bane all the way through school, I like numbers and figured lots of mental tricks (natural to me) for solving things, and was familiar with lots of number patterns (like powers of two), and so much of time answers were obvious to me, but I was marked down for not "showing" the work I never did. They didn't want me to know how to find the answer, they wanted me to crank through a rote procedure. As a simple example, if you add stuff up in your head there is no work to show.

      This even showed up in calculus when one old instructor wanted me to show my use of the "three step rule" for differentiation. What "three step rule'?! It appears that at some earlier time basic transformations for differentiation, which to me was a simple one step procedure, were divided into three separate "steps" for pedagogic reasons, I guess, which were entirely unnecessary, and not found in any recent text - basically manufacturing unneeded work.

      --
      Second class citizen of the New Gilded Age
    3. Re:How was this question graded? by Anonymous Coward · · Score: 4, Insightful

      "Show your work" is shorthand for "prove you didn't cheat".
      Just dropping down an answer means that as far as they can tell you copied it off a friend, looked it up online, etc.

    4. Re:How was this question graded? by beelsebob · · Score: 4, Insightful

      The problem is that so many of those "intuitive" tricks that we build up in our heads are not actually true. We have no concrete proof that they're valid steps in the simplification of the problem. By demanding that you right down the steps you take, the teacher can point out when you take a step that doesn't actually hold up.

    5. Re:How was this question graded? by Wrath0fb0b · · Score: 5, Insightful

      I'm sorry to hear that. As an instructor, I always encouraged my students to show their work for an entirely different reason.

      As I would explain: if you do the problem correctly, you will get full credit. If you get the problem wrong, I will go through the work you've shown and try to give you as much partial credit as I can justify. If you don't show much work, I can't give you any partial credit and so you'll get zero points on the question.

      This is the only fair way to do it. Students that get 90% of a problem right should get 9/10 possible points. But to do that, you really do have to encourage them to show their work in sufficient granularity for the instructor to grade it.

    6. Re:How was this question graded? by Anonymous Coward · · Score: 4, Insightful

      The correct answer is: Méiyou zúgòu de xìnxi. (There is not enough information)

      No, the correct answer is today's date minus the captains date of birth.

    7. Re:How was this question graded? by lewiscr · · Score: 5, Insightful

      I don't know what mental shortcuts you use, but I can prove that mine are valid.

      Why would I write down 162 + 199 and add it up, when I can just mentally add 161 + 200?
      Why would I do long multiplication of 50*49, when I can do (50*50)-50 in my head?

      I once watched a class mate add zero to a number on his calculator. Can we accept that there are some mental shortcuts that are valid?

    8. Re:How was this question graded? by Pseudonym · · Score: 5, Insightful

      "Show your work" is shorthand for "prove you didn't cheat".

      That's part of it. "Show your work" also gives you partial marks if you had the correct reasoning but made a mistake somewhere along the way. It also reveals to the teacher if a large proportion of the class doesn't understand the same thing, so the teacher can concentrate on this.

      But most of all, "show your work" is what real mathematicians do for a living. If you write a paper which says "the Goldbach conjecture is true, and I know because I proved it in my head", it will not get published because you need to show your work.

      --
      sub f{($f)=@_;print"$f(q{$f});";}f(q{sub f{($f)=@_;print"$f(q{$f});";}f});
    9. Re:How was this question graded? by ShanghaiBill · · Score: 3, Insightful

      "Show your work" also gives you partial marks if you had the correct reasoning but made a mistake somewhere along the way.

      NO!!! This is NOT what happens in America's schools. If this was all that happened, that would be fine. The problem is that that if a kid gets the correct answer, points are TAKEN AWAY for not "showing your work".

      If a kid is confident in his ability, and doesn't want to fall back on the crutch of "partial credit", there should be no requirement to "show work". That is just punishing smart kids by forcing them to do it "the stupid way". Schools should not be in the business of making kids dumber.

    10. Re:How was this question graded? by angel'o'sphere · · Score: 4, Insightful

      And why would you not write:
      162 + 199 = 161 + 200 = 361? Takes no time.
      And then you write: 50*49 = (50*50) -50 = 2450, takes no time either.

      If you can do stuff in your mind, you can as well write down what you did in your mind, or not?
      That is how I did it in school and no one complained.

      --
      Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
    11. Re:How was this question graded? by TheRaven64 · · Score: 2, Insightful

      If you write down 42 as an answer, the marker doesn't know if you guessed, if you just copied the answer out of the mark book, or if you actually worked it out. If you show the calculations then it's easier to tell these apart.

      When you're teaching maths, you're not teaching people to get the right answer to a problem, you're teaching them to be able to get the right answer to all problems in a category. Seeing the answer lets the marker know if they've succeeded in the first objective, showing the working lets them know they've succeeded in the second.

      --
      I am TheRaven on Soylent News
  2. Re:There is always an answer by bobbied · · Score: 1, Insightful

    I beg to differ... SOME questions have many answers with no single answer being more correct than another and sometimes there are questions for which there are no answers at all.

    Expecting all questions to be solvable from the information given is a commonly misunderstood issue. Critical thinking involves realizing that you may not be given all the relevant data and may need to find additional information to get a good answer. In other words, good problem solving involves thinking about the unknown, both the known unknowns and the unknown unknowns.

    Have an issue with Known unknowns vrs unknown unknowns? Let me illustrate what I mean. Known unknowns is understanding that you will have a calculable number of software bugs during a specific sized software project. You don't know what they will be, but you know they will happen and you can guess what it will take to fix them from experience, a known unknown. Unknown unknowns are things you simply cannot foresee, like your office being hit by a tornado in the middle of the project.

    --
    "File to fit, pound to insert, paint to match" - Aircraft Maintenance 101
  3. Re:There is always an answer by Obfuscant · · Score: 4, Insightful
    Having to use a sarcasm tag defeats the purpose of encouraging critical thinking. When the topic sentence is so clearly and patently false, maybe rethinking whether the remainder of the argument is meant to be serious or sarcastic before launching into a lecture or modding down is a good idea.

    But I see a lot of people didn't get it. Oh well.

  4. Re:There is always an answer by Hognoxious · · Score: 4, Insightful

    What have I got in my pocket?

    --
    Confucius say, "Find worm in apple - bad. Find half a worm - worse."
  5. Re:There is always an answer by alvinrod · · Score: 4, Insightful

    I'm going to assume you're being incredibly sarcastic here because life is full of problems for which there is insufficient data to determine a correct answer. There are a great many that do already have good answers, but at one point there was insufficient data to answer them.

    If you wanted to make this exercise more useful, I'd rephrase the question (to something that's not immediately obvious) and once they've figured out that they lack sufficient data, ask them what information they would need to produce an answer. Knowing that you have insufficient data to answer a question is one thing, but understanding what is missing and how to go about getting it is a highly valuable critical thinking exercise.

  6. Re:This question first appeared in 1841... by geekmux · · Score: 5, Insightful

    Mod up please. This is exactly the kind of quality information that makes me read the comments before the article. The entire discussion makes no sense without knowing this. Shame on The Washington Post for publishing making this sound like some controversial idiotic thing, without providing the basic background!

    Perhaps I could help explain with a math problem. Seems fitting.

    Since hype and bullshit are proven revenue streams, how many clicks and likes does it take to dismiss journalistic integrity and relevant information?

  7. Re:Fred Brooks interview question by Zontar_Thing_From_Ve · · Score: 4, Insightful

    if it's really as intended. But it's probably a typo that didn't get caught. They happen. Feynman has a story in one of his books about finding a math problem like

    Johnny observes three stars through his telescope. The stars' temperatures are X, Y, and Z kelvin. What is the total temperature observed?

    when he was asked to evaluate science textbooks for the school board in Pasadena.

    I looked at the original article which Feynman wrote and your summary, while extremely condensed and accurate enough for here, just assumes that the reader will get the point of Feynman's dislike of the question. I bet most here will miss it. The reason that Feynman objected to the question in the textbook is that in real life there is no reason at all to add the temperatures of stars, not that the question had a horrible mistake in it. That's very different from the question in the parent article, which is to test critical thinking.

  8. Re:At least 28 years old by Anonymous Coward · · Score: 2, Insightful

    You don't need to memorize the material, but it is an extremely important lesson to learn that such material exists, and it's even relevant to advanced mathematics.

    I don't remember most of my calculus days, but I do remember that most of my work consisted of trying random arbitrary approaches, and seeing which one advanced the problem toward the solution. Whether L'Hopital's rule, integration by parts, or other tactics I no longer remember, it's not always obvious how to proceed. Developing the skill to match a problem to a solution approach is vital.

    In the real world, the same skill is necessary for a lot of everyday analysis, perhaps best demonstrated by Randall Munroe's "What if?" series. The questions posed are often absurd, but the approach to answering them typically relies on making connections to apparently-unrelated (but similar) phenomena, allowing for some rough estimation of the original problem. More practically, these kinds of questions appear every day, in less obvious forms such as "How much more will it cost if we double the scale of this whole project?" or "If we add a Widget to the Wotsit, will the Frobozz still function?", usually accompanied by an impatient boss with very little technical skill...

    Getting back to the subject at hand, I expect the purpose of the question was not to seek any particular answer, but to gauge whether the students are able to consider non-obvious paths to a solution. Knowing the rules for boating licenses is one viable route. Random guessing is another. Giving up and complaining that the teacher didn't spoon-feed you enough information is not.

  9. Re:There is always an answer by Anonymous Coward · · Score: 3, Insightful

    Sneaky little Hobbitses. Wicked. Tricksy. False.

  10. NaN by cyn1c77 · · Score: 4, Insightful

    This problem is not sufficiently bounded to solve from a mathematical perspective.

    (That's the actual answer... You don't need to be over 18 if you are piloting the boat illegally and there may not even be a captain.)