This kind of teacher is the one who makes everything 4 million times harder than its supposed to be. However it is completely worth going throught the difficulty as you will be getting more prepared for the exam and will know the subject inside and out.

How to deal: Work really hard throught his class, trying to absorb the extra information, even if you know that it might not come for the exam. It'll come in use some time. Try your best! Sometimes this teacher might be unnecessarily unfair. But the hard work you put in will be all worth it