Quote Originally Posted by bogialaoleu View Post
Why do we use Education for Education system. And why do we use Educational for the sentence: "Reducing the size of classes may improve educational standards"?
I think the clue is that "we" don't do those things. Cambridge Dictionaries writes one form, you write another, your teacher thinks a different form is correct. Members here will disagree.
People use different forms. You can't guarantee against the loss of marks this way.