I just took the HESI A2 yesterday. I used the "HESI Admission Assessment Exam Review Ed. 3" by Elsevier. Found it at the college bookstore. It did a fine job at preparing me. It is just a guideline, though, you need to have a wider breadth of knowledge than just the vocab that they have listed.
The math section had a lot of ratio questions, I was surprised.
Each school has different requirements for testing. Check your school for what subjects they will be testing for. I'm applying to UTA and they just required Math, Grammar
, Vocab and general knowledge.
Each section has 55 questions.