Matt — Creativity is certainly to be encouraged, but creativity is not mis-understanding and misusing the fundamentals of math. If the teacher had taught (correctly) that the number of operations is on the left, then the answers given by the student are incorrect. The two examples that are causing so much upset just happen to come out the same result when performed incorrectly but, but as the author shows, this is not the case if the operator is different. The bananas example is a nice illustration of why it’s important to have the correct mental model of the number of operations being on the left—imagine a mistake like this in a programmer’s code, where the right side value is wrongly used for a repeat loop count. We want more successful STEM students, right? Showing that a methodology is wrong is entirely different from squashing creativity. As long as the curriculum requires the teacher to teach students the correct mental model, then it is both fair and helpful to mark both of the illustrated answers as wrong.