What can I do about a lecturer who isn't clear enough to understand? I'm a Maths university student and I just can't seem to learn anything from one of my lecturers.

I understand we, as students, should do personal research on our subject. But he just doesn't make any sense.
He'll teach one thing, then during that, he'll RANDOMLY pull out something out of the blue WITH NO EXPLANATION.
Not even a "Well we do this because...".

He explains new concepts, like he's talking to PhD graduates.

I've spoken to him about it and all he says is "He loves teaching".

I've already failed 2 of his module exams because of this and am having to resit them.

What can I do?
Here are some ideas for you to consider.


Seek out a more advanced student who has already made it through the course, for guidance.
If the class has a TA, visit the TA's office hours assiduously.
If the course has a textbook, read it carefully.  If it doesn't, ask the professor for a textbook that is reasonably well aligned with his approach.
Make sure you have a course syllabus.  See if a careful perusal of the syllabus helps.
If you have an advisor or mentor professor, let him or her know.  If you don't have one, try to find one, by talking to another professor in the department that you think may be knowledgeable about the course content.
Let a department administrator know about your difficulties.
Consider withdrawing from the class.