3.OA.A

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  • #3075
    dlward
    Member

    I am asking this as a grandparent of a 3rd grade student. Is there anything in Common Core 3rd grade mathematics that would make the following scenario acceptable? I have been a Secondary Mathematics specialist for many years and I believe there is a an error in the thinking of this teacher but I want to make sure that I am not missing anything.

    The student is completing a problem with the following instructions.
    “Pick a number to use for the number of people or animals.”
    The student enters the number they select in an answer blank.

    The student is then asked
    “How many Human Legs?” and then asked to write a number sentence and produce a drawing.
    Here is the issue, the teacher is saying that the student must write the number sentence with the number of humans written first and the number of legs that the human has written second. For example 10×2. The teacher marks the student wrong if they write 2×10. The teacher claims that requiring students to write the numbers in a particular order is Standard for Mathematical Practice #6: Attend to Precision. Is there something I am missing – I am concerned with the conceptual understanding that is being developed by this teacher’s practice. I would appreciate your feedback. Thanks

    #3079
    Bill McCallum
    Keymaster

    Well, I don’t know the whole story here, and getting caught in the middle of a battle between a grandparent and a teacher is the last thing I want to do, but maybe you could use MP6 in your response to this teacher. Attending to precision includes attending to precision in the asking of questions. From your description it does seem that your grandchild answered the question correctly as posed, since the question did not specify a particular order in which the product must be written (nor would that have been a good idea). I agree that it is unacceptable that a mathematically correct answer should be marked wrong.

    Now, I think I know where the teacher is coming from (you probably do too). The teacher has in mind that the student should be thinking of 10 groups of 2, and 3.OA.5 does suggest this would be written as $10 \times 2$:

    3.OA.5 Interpret products of whole numbers, e.g., interpret $5 \times 7$ as the total number of objects in 5 groups of 7 objects each.

    Still, your grandchild’s answer is not wrong, because $10 \times 2 = 2 \times 10$.

    It seems to me all this could come out in classroom discussions, and this would be the appropriate place to discuss the answer. That is, without saying the answer is wrong, you could ask the student to explain their thinking, and see how they decided to write $2 \times 10$, and that could lead to some good discussion.

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