Transition to college life from school means a lot in the way we study the subjects. We can expect no more spoon feeding.
You would have seen your Maths teacher working out each and every problem when you were studying 12th standard. You would have taken tuitions. You would have had guides, notes with all answers to make things easier for you. Nothing apart from the given questions will appear in the question paper.
And now you are into an entirely different world. Don't get scared or don't curse your lecturers. It is an accepted trend that the lecturers will not solve even 25% of the given problems, but instead leave them to you to solve and come to their cabins if you have unsolved issues. The truth will be they will not have enough time to complete the syllabus if they start to work out all the problems. Moreover leaving it to you to work out the other problems helps you to understand the subject and concepts more clearly. Tuitions are available but very few and more costly and even there it will be just explaining concepts and not making you to study the subject. Guides and notes are available in the market but will not be sufficient enough to substitute self-study.
The best thing is to study the subjects sincerely with proper understanding, not just for the sake of exams but also for the sake of knowledge.
You will have lot of freedom, much enough to spoil yourself. But it is you who should monitor yourself since you will have no one to be behind you and for spoon feeding.