The AFQT is often mistakenly called the “overall ASVAB score.” You commonly hear someone say, “I got a 67 on the ASVAB,” or “My ASVAB score was 92.” That’s not correct; it implies that the AFQT is derived from all nine subtests of the ASVAB, and it’s not. The AFQT score is computed from just four of the ASVAB subtests that measure your math and communicative ability.
The other written test format is the Student ASVAB which is given at high schools, vocational schools, or colleges. This test lasts approximately three hours. The Written Arithmetic Reasoning subtest of the ASVAB consists of 30 multiple choice questions, which must be answered in 36 minutes. Below are a few sample questions which are very similar to the actual questions you'll see on the ASVAB:
Because most of the concepts and methods used by the military, and many of its systems are not found in commercial branches, much of the material is researched, designed, developed, and offered for inclusion in arsenals by military science organisations within the overall structure of the military. Military scientists are therefore found to interact with all Arms and Services of the armed forces, and at all levels of the military hierarchy of command.

Limited Duty Officer: due to the highly technical nature of some officer billets, the Marine Corps, Navy and Coast Guard employ a system of promoting proven senior enlisted members to the ranks of commissioned officers. They fill a need that is similar to, but distinct from that filled by warrant officers (to the point where their accession is through the same school). While warrant officers remain technical experts, LDOs take on the role of a generalist, like that of officers commissioned through more traditional sources. LDOs are limited, not by their authority, but by the types of billets they are allowed to fill. However, in recent times they have come to be used more and more like their more-traditional counterparts.
Law prohibits applicants in Category V from enlisting.[6] In addition, there are constraints placed on Category IV recruits; recruits in Category IV must be high school diploma graduates but cannot be denied enlistment solely on this criteria if the recruit is needed to satisfy established strength requirements. Furthermore, the law constrains the percentage of accessions who can fall between Categories IV-V (currently, the limit is 20% of all persons originally enlisted in a given armed force in a given fiscal year).[6]

I thought I was just buying an extra book, that I would most likely not put attention to. But, it was not. This book is filled with practice questions, which I got to study before hand thanks to the "2015 / 2016 ASVAB For Dummies". These two books makes a great combination. One to study and the other to test how far you have improved by testing yourself. I am glad I bought it. I recommend it to everyone who is thinking of taking the ASVAB or the AFQT. Just have in mind, that this book is all about questions, of course it will give you the correct answer in the back of it, but it will not go into detail as much as the "2015 / 2016 ASVAB For Dummies" book.
Additionally, many ASVAB practice tests have a section explaining the answer choices. It can be tempting to read the explanation and think that you now have a good understanding of the concept. However, an explanation likely only covers part of the question’s broader context. Even if the explanation makes sense, go back and investigate every concept related to the question until you’re positive you have a thorough understanding.
Military law introduces offences not recognised by civilian courts, such as absence without leave (AWOL), desertion, political acts, malingering, behaving disrespectfully, and disobedience (see, for example, Offences against military law in the United Kingdom).[23] Penalties range from a summary reprimand to imprisonment for several years following a court martial.[23] Certain fundamental rights are also restricted or suspended, including the freedom of association (e.g. union organizing) and freedom of speech (speaking to the media).[23] Military personnel in some countries have a right of conscientious objection if they believe an order is immoral or unlawful, or cannot in good conscience carry it out.
Test scores provide only one measure of your skills and abilities.  Test scores and grades, combined with information about your interests, values, skills, and achievements may help you select appropriate occupations for career exploration.  As you explore careers, you can compare your skills with the skill requirements of occupations in which you are interested.