Three Answers

RIGHT, WRONG, NOT WRONG

When students give answers to math questions they sometimes will give an answer that is not what the teacher really wants but it is equal to the correct answer or is written in a different way. For me, those answers fell into the "Not Wrong" category. That told the students two things. First and most important to them, their answer was not counted wrong. Second, there was something else I wanted for that answer. They got the benefit of not counting the answer wrong but they knew there was a different answer or a different way of writing the answer that I wanted them to understand.

There are answers that are "Right." There are answers that are "Wrong." There are answers that are "Not Wrong." Here is an example:
Let's say the student is asked to solve P=2L + 2W for L.
For me the "Right" answer is L=(P-2W)/2.
A "Wrong" answer could be L=P-W.
A "Not Wrong" answer could be L= -W + .5P.
Some teachers might very well consider that that last answer is just as "Right" as my first answer and that is fine. My point here is that there are situations in which the student may give an answer in a way that really isn't wrong but is not in the form that the teacher might want, in that situation, at that time. In the above example if the teacher had specifically told the students that there were to be no decimals or negative signs in a formula, then that "Not Wrong" answer would be "Wrong."
My experience with most students is that when they hear that an answer is "Not Wrong", they will attempt to understand the different type of answer that the teacher wants and try to do it that way next time.

There are other situations in which there are multiple right answers. A simple example would be the following:
What is the probability that a card randomly drawn from a standard deck is a diamond?
"Right" answers could be 13/52, 1/4, 25%, or .25. Of course if the directions had stated that the answer had to be a fraction in simplest form, then the only "Right" answer would be ¼.

The concept of "Not Wrong" might also apply to the method that a student uses to find an answer. It is good for students to know that there are multiple ways of solving a problem. However the teacher might want the student to use the most efficient method and/or a method that can be applied to many other problems. For example a student might use the Guess and Check method to successfully solve a certain problem. The teacher might call that method "Not Wrong" if they had wanted the student to use a more efficient strategy.

As you can imagine the concept of "Not Wrong" is in the eye of the beholder and the situation. What is "Not Wrong" to one teacher might be "Wrong" to another teacher and "Right" to another teacher. The concept of calling some answers or methods, “Not Wrong” can be an effective teaching tool that shows respect for student thinking but also teaches that there is something else they need to learn.