I'm going to cheat on my exam
Are you failing your class? Why would you cheat?
So I can get high grades in it.
It's not right to cheat on exams. You should be studying instead.
It's fine, cause we don't learn anything in school.
It may seem frivolous now, but actually, we learn most of the important stuff at school.  Studying hard and learning the material now will make it easier for you to succeed in more practical pursuits later on.