Sometimes, you want to provide feedback on failed answers in short answer questions. The way to do this is to add a last answer and set it to catch Any answer in Validation options > Comparison with student answer. ## Example 1: Equation of a polynomial

The main purpose when using this feature is to compare the student's answer with the correct one. Let's ask the following question: You can add dynamic feedback to the question based on the student's answer. For example, in this question, you could be interested in graphing the student's response and comparing it to the correct answer: To do so, you have to write `parameter answer = 0` in your CalcMe algorithm and, from then on, the student answer will be stored in a variable called `answer`. For the feedback example you just looked at, you must end up with this: Finally, you have to add an answer blank for the wrong answers and use the customized feedback. ## Example 2: Roots of a polynomial

Another purpose of using this feature is to provide the student with the steps they should have followed to answer the question correctly. Let's ask the following question: You can add dynamic feedback to the question based on the student's answer. For example, in this question, you could show the student's procedure to answer the question correctly. Moreover, you can also show why the provided answer is not appropriate. To do so, as in the previous example, you have to write `parameter answer = 0` in your CalcMe algorithm and, from then on, the student answer will be stored in a variable called `answer`. For the customized feedback example you just looked at, you will need to access the two answers given by the student and calculate the value of the polynomial in those points. The algorithm must end up with this: Then, you have to add an answer blank for the wrong answers and use the customized feedback for it. Keep an eye on the used notation! Finally, you have to add the general feedback showing the procedure to solve the problem. 