I found NCLEX-PN to have been difficult, once I got to question #60 and beyond. The computer shut down at 85, and I wasn't sure that I passed. I still remember a great deal of the questions to this day, and I tested in 2006. In retrospect, I was more prepared than I thought I was, and I was able to think through the questions that were difficult. Had only one math question (the first one). I did have several pick all that apply in a row, and that flipped me out.
Hindsight is 20/20. I remember reading a post 6 months later where a person said to look at the select all that apply as true/false questions, and not to look at all of the selections as a whole. Look at each choice and say to yourself "Is this true in relation to the question or is it false?" If it is true, select it, if not, do not choose that one. I passed, anyway, but it would have made my life easier had I actually saw it that way, then. I wish I remembered who posted that, this person gave pearls of wisdom, and I would have thanked that person perfusely. Good luck and as someone else said "study smart".