Dr. Li's AP Prep Classes really helped me prepare for my exams. I took his AP Precalculus course and his practice exams helped me self-study for one exam and get a 5 on it. 

It was difficult to self-study for the exam on my own as there was little resources on AP Precalculus online, as it is a new exam. Dr. Li was able to give me the information and practice I needed. The content in his classes actually applied to the exam, as some of the questions were the exact format of those I was tested on. I would highly recommend his classes for anyone who wants to do better on their AP exams!