how do we know that some kids are giving us the wrong answer if they say they got it Right

first thing to try is to check their answer to see whether it answers the question correctly.

If you can't do that, you do not yet understand the problem.

Even if you have trouble with the question, you should be able to follow their solution ...

OK Thank You

More advice: Don't even look at answers to questions that were posted more than 24 hours ago. We administrators rarely look at questions posted more than 24 hours ago. We usually delete newer wrong answers.

ok what about the second one

What is the second one?

what if it's a teacher how do tell the difference

Check any suspected wrong answer with your reading assignment or Google it. Most of our official tutors have their picture icon next to their name. And yes, even we occasionally make mistakes. We are human.