The ASVAB also known as the Armed Services Vocational Aptitude Battery is a test that measures your aptitude which is how well you do something.  A common mistake by most people is thinking that it is a measure of you IQ. Many people either forget this or don’t know this and they get worked up about the exam.  Saying that, it is also important to take a ASVAB sample test to insure you know what type of questions will be asked.    Another thing to keep in mind is every person in the armed forces has to take the exam and you are not being called out to take it. 
I just had to thank you guys for the test prep! I am a former Marine that decided to reenter the military and much to my surprise, I had to retake the AFQT!!! The last time I even looked at a math or English problem had to be at least 6 or seven years ago. I bought the guide as a last minute prep, I mean maybe 5 hours before the test. Like I said, I didn't even know I had to retake the test and had ZERO preparation! The job I wanted required a pretty high GT score and I was nervous about even passing the test let alone receiving the score I needed. I read the guide through only once before test time and needless to say, the only way I passed was thanks to your refresher!! Sgt. Brian

The first recorded use of the word military in English, spelled militarie, was in 1585.[2] It comes from the Latin militaris (from Latin miles, meaning "soldier") through French, but is of uncertain etymology, one suggestion being derived from *mil-it- – going in a body or mass.[3][4] The word is now identified as denoting someone that is skilled in use of weapons, or engaged in military service, or in warfare.[5][6]
The ASVAB test is taken by individuals interested in joining the U.S. military. It may be taken by high school students in the 10th, 11th or 12th grade. Or, it may be taken by someone who has earned a GED or higher degree. Along with determining your suitability for enlistment, the score you receive on this test lets officials know what military occupational specialties you may qualify for. 

All test takers are given a summary results sheet that shows their percentile score in every test area. A percentile score of 50 means that a score was achieved that was better than 50 percent of all test takers. Percentile scores are given specifically for test takers of their gender and their grade level. Information obtained from the test is only shared with agencies within the Department of Defense. Test takers are informed that their specific scores will be used for up to two years for recruiting purposes. After two years, test scores will be used for research purposes only.
Don’t be fooled by the appearance of the low numbers, the algorithm that computes the AFQT is very sophisticated. Just because your ASVAB score is 40 doesn’t mean that you only got 40% of the questions correct, it could simply mean that you lack strength in one area, but succeed with high praise in another. Your ASVAB score is only a means by which you are categorized for available positions; it is by no means a measure of intelligence.

This course is designed to help you dust the cobwebs off information you may have learned long ago or boost your scores if you have already taken the test (or a sample test administered by a recruiter) and did not meet the score you needed for the occupation you desire. This review is particularly helpful if you have been out of school for some time, did not graduate a standard high school program, or either did not take or performed poorly in classes related certain subject areas (e.g. shop or automotive classes). Within each subject area, the lessons build on one another, so we will help you progress in a logical manner in bite-sized, 10-minute-or-less chunks. Skip to the lessons that you know you need to focus on, and even jump to specific portions of the videos using the video tags. Use the quizzes, chapter tests, and course exam to see how you're doing and refocus your studies as necessary.
An important part of the military intelligence role is the military analysis performed to assess military capability of potential future aggressors, and provide combat modelling that helps to understand factors on which comparison of forces can be made. This helps to quantify and qualify such statements as: "China and India maintain the largest armed forces in the World" or that "the U.S. Military is considered to be the world's strongest".[29]
The Mathematics Knowledge section of the exam measures your knowledge of various math areas, such as algebra and geometry. You may be asked to find the square root of a number or the volume of a brick with given dimensions. Algebraic problems may require finding the value of “y” in a given equation. A review of math symbols—such as ≠, ≤, and √—can help you solve the given problems much faster, and using our ASVAB math study guide to practice answering the algebra and geometry questions on the test can help increase your overall AFQT score. The CAT-ASVAB has 16 questions in 20 minutes; the paper-and-pencil version has 25 questions in 24 minutes.
General Science tests the ability to answer questions on a variety of science topics drawn from courses taught in most high schools. The life science items cover botany, zoology, anatomy and physiology, and ecology. The earth and space science items are based on astronomy, geology, meteorology and oceanography. The physical science items measure force and motion mechanics, energy, fluids, atomic structure and chemistry.

Capability development, which is often referred to as the military 'strength', is arguably one of the most complex activities known to humanity; because it requires determining: strategic, operational, and tactical capability requirements to counter the identified threats; strategic, operational, and tactical doctrines by which the acquired capabilities will be used; identifying concepts, methods, and systems involved in executing the doctrines; creating design specifications for the manufacturers who would produce these in adequate quantity and quality for their use in combat; purchase the concepts, methods, and systems; create a forces structure that would use the concepts, methods, and systems most effectively and efficiently; integrate these concepts, methods, and systems into the force structure by providing military education, training, and practice that preferably resembles combat environment of intended use; create military logistics systems to allow continued and uninterrupted performance of military organisations under combat conditions, including provision of health services to the personnel, and maintenance for the equipment; the services to assist recovery of wounded personnel, and repair of damaged equipment; and finally, post-conflict demobilisation, and disposal of war stocks surplus to peacetime requirements.