Also consider that this question, or a close variant of it, gets asked about once every 2-3 weeks or so. Using the search feature and searching for "math book" or "math study" or something similar should turn up loads of previous discussion on this topic.
I don't think I've ever seen it repeated so close before (not that I check every day ... but still: when someone's asking a question that's practically identical the the most-recently-asked Ask HN ... you'd think they wouldn't ask :)