Hi,
There is some merit to what the other poster was saying. We definitely feel that a strong grasp on fundamental concepts is more important than focusing on just learning how to solve difficult questions. In fact, our instructors have sometimes found that the best way to get high scorers to do better in quant is to take them through drills in the Foundations of GMAT Math book. The less you have to think about the content and the more familiar you are with it, the better you will be able to apply these concepts easily to more tricky problems.
That being said, the advice contained in our advanced sections is definitely worth reading. There are some good strategies in there that will really help you hone your skills once you have that foundational knowledge that is key to answering questions. The strategies covered in the advanced sections are particularly important for those looking to score high, but can also be used by any level.
Let me know if you have any further questions!
Best Wishes,
Caitlin Clay
Student Services Associate
Manhattan GMAT