The HESI entrance exam is actually really not that hard. They cover Reading Comprehension, Vocabulary, Grammar, Math, and Anatomy and Physiology. I really thought I was going to walk out of there with a 70, but ended up with a 90 overall. Don't stress about it. Pick up one of those practice test booklets, run through it once or twice, and go take the test. Really easy. I think they give you about 3-4 hours to complete the test, but you generally don't need that much time. I'm not sure what you mean by the vocal section? Unless you're talking about the Exit HESI, which I assume is nothing like the entrance exam. Oh, and yes, they do give you a calculator to use. Good luck!