The Hershey Bar Problem (#3Act Revised and Updated)

About a month ago, I posted The Hershey Bar Problem in which I discussed, among other things, the ways in which I rip off other teachers work. This is an example of that. This is a Dan Meyer rip-off pure and simple. I just want to cover myself in that regard.

As usual, all constructive feedback is welcome.

Here’s the rest:

Act II – Dimensions of the Hershey Bar or Dimensions of the segments after the cuts.


Sequel #1

Sequel #2

3 thoughts on “The Hershey Bar Problem (#3Act Revised and Updated)

  1. Hi Andrew, I read with great interest your discussion on the Hearshey Bar Problem. I am about to teach congruence to my Year 8 class and I think this is a fantastic way to get a lot of discussion going between the students.

    One problem though – when I click on the hyperlink ‘go and read the original post’ on this page, the link takes me now where. I would really like to read this as this will be my first experience of teaching this problem.

    Looking forward to hearing from you.

    Robert McGregor
    Rayong English Programme School, Thailand

  2. Thank you for letting me know that. I think that I deleted that post a while back when I wrote this one to replace it. I know which post I am referring to. I remember writing it, but when I look back in my posts, it isn’t there.

    So apparently at one point, I decided that this post sufficiently replaced that one. I assure you, that was a pretty forgettable blog post.

    This one ( ), on the other hand, is not. And it shows some student work related to Hershey Bar Problem with some discussion of the aftermath. Please let me know if you have any more questions or thoughts. Once again, I appreciate the feedback on the dead link.

  3. In their fantastic book ‘5 practices for orchestrating productive mathematics discussions’ Smith and Stein state that before providing an open ended problem to a class, the teacher must anticipate what possible solutions, both correct and incorrect, students might consider when working on the problem. With the Hershey Bar Problem, my reason for asking about your original posting was to see if I could glean any further information as to what these possible solution pathways might be. I have been able to come up with 6 possible solution pathways so far, as follows;

    1. use the smaller Hershey rectangles as a unit of measure
    2. work out correctly the area of each of the three individual pieces and compare.
    3. incorrectly focus on adding the perimeters of each piece as a solution to the problem
    4. realise that the two smaller pieces, when joined together to make a triangle, have the same area as the one larger piece
    5. realise that when the two smaller pieces are joined together they make a triangle congruent with the one larger triangle. This congruence is discovered when students recognise that corresponding angles and sides are the same.
    6. draw in an auxiliary line (as shown in one of your photos).

    Can you think of any other pathways of exploration students may go down when working on this problem?

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