# MathEntry – Evaluation stages

You specify how the student’s input is evaluated through a list of evaluation stages. AlgebraKiT will evaluate these stages in the order that they are specified and stop at the first stage that matches the student input.

Consider the following example, which defines three stages to evaluate the student’s input.

The first stage matches the expression $y=x^2+x$ and its commutative variations, which are $y=x+x^2$, $x^2+x=y$ and $x+x^2=y$. If the student inputs any of these expressions, then this input will be evaluated as a correct final answer.

If the student enters the expression $y=x\cdot x+x\cdot 1$, then the first stage is not satisfied and AlgebraKiT will proceed to the next stage. This stage matches because the input can be rewritten to $y=x^2+x$. The stage specifies that the input should be evaluated as an intermediate step. Therefore, the student will see that his input is correct but not yet finished.

If the student enters the incorrect expression $y=x\cdot x + 1$, then also the second stage does not match, but the third one does. This stage specifies that error feedback should be given. The feedback is specified by the author as we will see later.

If none of the stages match the student input, then AlgebraKiT will assume that the input is incorrect. There is an exception: If no evaluation stages are specified, then AlgebraKiT will accept every input as the final answer.