Testing out of college courses using programs like the College Level Examination Program (CLEP) can provide students with college credit for subjects that they have not studied on a college campus but have mastered by other means (independent study, on-the-job training, and previous coursework) and it will save time and money. But how will a student know if this approach is right for them? This guide is intended to answer that question for students who are interested in taking CLEP's Natural Sciences exam. It provides general information on the CLEP program along with suggestions on how to preparing for the exam. There is a subject breakdown of the exam, the topics that will be covered and a list of online resources which can be used to study or review these topics. There are sample problem solutions, crib sheets, vocabulary and two practice tests; each of which is structured like the official exam with 120 multiple choice questions. The practice tests come with answer key and an explanation section on the reason why each answer is the right one.