Command over the U.S. Armed Forces is established in the Constitution. The sole power of command is vested in the President by Article II as Commander-in-Chief. The Constitution presumes the existence of "executive Departments" headed by "principal officers", whose appointment mechanism is provided for in the Appointments Clause. This allowance in the Constitution formed the basis for creation of the Department of Defense in 1947 by the National Security Act. The DoD is headed by the Secretary of Defense, who is a civilian and member of the Cabinet. The Defense Secretary is second in the U.S. Armed Forces chain of command, with the exception of the Coast Guard, which is under the Secretary of Homeland Security, and is just below the President and serves as the principal assistant to the President in all defense-related matters.[16] Together, the President and the Secretary of Defense comprise the National Command Authority, which by law is the ultimate lawful source of military orders.[17]
As of 31 December 2010, U.S. Armed Forces troops were stationed in 150 countries; the number of non-contingent deployments per country ranges from 1 in Suriname to over 50,000 in Germany.[30] Some of the largest deployments are: 103,700 in Afghanistan, 52,440 in Germany (see list), 35,688 in Japan (USFJ), 28,500 in South Korea (USFK), 9,660 in Italy and 9,015 in the United Kingdom. These numbers change frequently due to the regular recall and deployment of units.
Reading page after page of boring content can cause the strongest minds to wander. Taking practice tests are a great way to break up the monotony of studying. Taking a practice test challenges you and keeps you interested in the material. Then you can review your test results and go over the questions you got wrong committing the right answer to memory. It’s a great, streamlined way to learn.

The test must be completed if you wish to serve in the Army, Navy, Marines, Air Force, or Coast Guard. The test can also be taken as a career-exploration tool if you are a high school sophomore, junior, or senior. It takes approximately three hours to complete. If you take the computerized version of the test, results are given immediately. If you complete a paper and pencil test, you’ll get results within two weeks.

Welcome to ASVAB Practice Tests, a free website that is designed to help you with your ASVAB test prep and review. Each of our free ASVAB practice tests includes challenging practice questions along with detailed explanations. Whether you are preparing for a career in the Army, Navy, Air Force, or the Marines you will need to pass the ASVAB test. If you study for this test it will make a big difference in your final score. Get started now with our free ASVAB practice tests!
As you go along, keep in mind that the ASVAB practice test is just that: practice. Memorizing these questions and answers will not be very helpful on the actual test because it is unlikely to have any of the same exact questions. If you only know the right answers to the sample questions, you won’t be prepared for the real thing. Study the concepts until you understand them fully, and then you’ll be able to answer any question that shows up on the test.

I have already served in the military years ago. But I wondered if there was a primer that might have helped me improve my test scores. I think this book would help. Unfortunately it's hard to learn enough from a book to do well on the math and reading comprehension of the ASBAB test. Study hard in math and English class in high school. It's hard to cram from a book to pass a comprehensive test that covers many topics. I think it may give you a few extra points, however.
The CAT-ASVAB is a computer-based exam that is only provided at Military Entrance Processing Stations (MEPS) for enlistment purposes. The test is customized based on the taker’s answers, so if one question is answered correctly, the next one will be more difficult. This exam is timed, although users have the option of pacing themselves throughout the exam. However, it is not possible to go back through the test and check answers or change responses after they have been submitted. The CAT-ASVAB is broken down into 10 subparts, including basics such as arithmetic and verbal skills as well as auto information, electronics, shop, and mechanical knowledge.
Mathematics Knowledge tests the ability to solve problems by applying knowledge of mathematical concepts and applications. The problems focus on concepts and algorithms, and involve number theory, numeration, algebraic operations and equations, geometry, measurement and probability. Mathematics Knowledge is one factor that characterizes mathematics comprehension; it also assesses logical thinking.