As a general practice, you should use the PREVIEW mode to check examples that are correct and also incorrect to check the grading. In most cases, the defaults will be fine and the Edulastic auto-grader will identify the correct context, but in some cases, you will need to manually adjust the grading using these options.
Here is an example:
Write the sum of the following fractions in simplified form.
Now let's go to preview mode and check how this works in a few cases:
correct and incorrect answers behave as expected.
BUT, as we required the student to simplify their answer by removing common factors, we should try 4/6:
But here the automatic grading considers this as a valid answer (it is mathematically equivalent to 2/3 which is the basis of the autograding).
In order to change the grading we need to specify an additional option by using the green CHANGE button under the expected answer field:
Then select "SIMPLIFIED".
Now the grading is working as we intend it to:
If you would like to give students partial credit for a mathematically equivalent answer that is not simplified, then you can do this by giving alternative answers with different point levels.
Also, it could be helpful to check this article about apparent grading issues.