I am looking for a bank of drills or sets of example questions that just focus on more complex math issues. e.g. here's a set of figures how would you arrive at X, now that you have X what do you need to get Y. Any examples of cases with good quant would help too. Also, I am not preparing for an interview that is going to have particularly hard math it is just my weakest point right now so I would like to focus more heavily on it. Thanks for any feedback.