Fifth-grader Noelle had an aha moment during a class discussion about Ways to Make Two-Tenths (see Figure 6.1). She mistakenly thought that 2 divided by 10 was 5, but came to understand that the solution 5 did not make sense. I asked Noelle, “How were you convinced that 2 divided by 10 is https://www.w3.org/1998/Math/MathML"> 2 10 https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781032681924/37ad5977-a09c-412b-bb65-209b0375487d/content/inline210_B.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> ?” She replied, It was just Austin explaining that 2 is smaller than 5 so that answer does not make sense. If you did 2 divided by 10 and you thought it was 5 then that wouldn’t work because 2 is smaller than 5. For 2 divided by 10, the pieces are going to be really small, they are not going to be 5. https://www.w3.org/1998/Math/MathML"> 2 10 https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781032681924/37ad5977-a09c-412b-bb65-209b0375487d/content/inline210_B.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> makes more sense. Those are small pieces. When we talk about it, we learn more, and we figure it out. We sometimes need to argue about it to make it make sense.