Math Curmudgeon is listing “things we need you to stop saying.” Number 1: “The right answer isn’t important. It’s knowing what you’re doing.” The right answer is the whole point of doing the problem … has always been, is now, and will always be, the Curmudgeon argues. The “knowing what you are doing part” leads to the right answer. If it doesn’t, then you don’t know what you are doing.
What we should be saying is “The right answer is vitally important … so important that we also want students to explain the method and how we all know the answer is correct; they must be able to detect an error if it occurs and describe how to fix it so that the solution IS correct.”
“You can’t detect errors unless you know the right answer, or at least have a sense of what that right answer should be,” the Curmudgeon writes.