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. Together, the President and the Secretary of Defense comprise the National Command Authority, which by law is the ultimate lawful source of military orders.
In the 1950s, the military adopted a single exam known as the Armed Forces Qualification Test (AFQT). Used as a screening tool, the AFQT measured a recruit’s ability to absorb military training and their future potential. It was supplemented by service-specific battery tests for the purposes of MOS classification. In 1972, the Department of Defense determined that all services should use one exam for screening and assigning individuals to an MOS. The AFQT was phased out over a two-year period in favor of the current Armed Services Vocational Aptitude Battery (ASVAB) test.
One set of ASVAB scores – Career Exploration Scores – tells you your current strengths in verbal, math, science, and technical skills. The scores allow you to compare your test performance with that of other students at your grade level and can help you determine your readiness for further education and training in different career areas. You will also receive a Military Entrance Score that is important for entry into the Armed Services. You can discuss your score with a military recruiter.
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.