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.
The ASVAB is a series of tests developed by the Department of Defense and is used by the U.S. Army to determine whether you have the mental aptitude to enlist. The ASVAB also helps determine which Military Occupational Specialties (MOS) you qualify for. The ASVAB is required to enlist in the U.S. Army and is valid for two years. The ASVAB may be given in a computerized version at a Military Entrance Processing Station (MEPS) or in a paper version at various Military Entrance Test (MET) sites around the country or at high schools and colleges. 

There are different minimum AFQT score requirements for enlisting in the Army, Navy, Marines, Air Force, and Coast Guard, although requirements will vary depending upon whether you have a high school diploma or a GED. Minimum score requirements change on a fairly regular basis, with higher scores being required during times of above-average enlistment levels. Enlistment bonuses, which are determined by your choice of military occupation, may also be influenced by AFQT scores.

Standard Scores are scores that have a fixed mean and standard deviation in the population of examinees. A Standard Score indicates how many units of the standard deviation a particular score is above or below the mean. In the case of the ASVAB subtests, the mean is set to 50 and the standard deviation is set to 10. Thus, a Standard Score of 40 indicates that the examinee scored 1 standard deviation below the mean. A Standard Score of 70 indicates that the examinee scored 2 standard deviations above the mean. To learn more about how standard scores are derived and used, click here.
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.
You often hear people say something like, "I got a 70 on the ASVAB." What they are talking about is the ASVAB AFQT score or Armed Forces Qualification Test Score. Many people think the AFQT score is the overall ASVAB score, but that's not correct. In fact, the AFQT score is derived from only four of the nine ASVAB subtests: Paragraph Comprehension (PC), Word Knowledge (WK), Mathematics Knowlege (MK), and Arithmetic Reasoning (AR).
On the Learning Tools website, your options include 10-question ASVAB General Science practice tests. These ask you to use terms in context, define terms, and complete basic math problems. You may also be asked to categorize items and answer questions related to general scientific facts. The ASVAB Math Practice Tests are exercises that challenge your ability to correctly answer word problems based on sales and profit, speed, time, area, and other relational concepts.

Just as the President, the Secretary of Defense, and the Secretary of Homeland Security, are in charge of the entire military establishment, maintaining civilian control of the military, so too are each of the Defense Department's constitutive military departments headed by civilians. The four DoD branches are organized into three departments, each with civilian heads. The Department of the Army is headed by the Secretary of the Army, the Department of the Navy is headed by the Secretary of the Navy and the Department of the Air Force is headed by the Secretary of the Air Force. The Marine Corps is organized under the Department of the Navy, however it is still considered a separate and equal service. The Coast Guard is under the Department of Homeland Security and receives its operational orders from the Secretary of Homeland Security. However, the Coast Guard may be transferred to the Department of the Navy by the President or Congress during a time of war, thereby placing it within the DoD.[19]
Development of military doctrine is perhaps the more important of all capability development activities, because it determines how military forces were, and are used in conflicts, the concepts and methods used by the command to employ appropriately military skilled, armed and equipped personnel in achievement of the tangible goals and objectives of the war, campaign, battle, engagement, action or a duel.[31] The line between strategy and tactics is not easily blurred, although deciding which is being discussed had sometimes been a matter of personal judgement by some commentators, and military historians. The use of forces at the level of organisation between strategic and tactical is called operational mobility.
Again, the ASVAB is a wide-ranging exam covering many different areas. The designers of ASVAB practice tests, at least the high quality ones, know this and have spent time researching past tests to come up with practice tests that feature questions covering areas commonly tested for on the real exam. Thus, taking practice tests is a great way to focus on the material that matters most and avoid wasting your time studying content that likely won’t be on the test.

Candidates taking the ASVAB are given a AFQT (Armed Forces Qualifying Test) score which is simply a combination of your scores from four tests (Arithmetic Reasoning, Mathematics Knowledge, Word Knowledge, and Paragraph Comprehension). This AFQT score is represented as a percentile (from 1-99) which depicts how well you scored compared to other test takers. For example, if your score is a 57, this means that you scored better than 57% of the other test takers. The AFQT score is used to determine whether you are qualified to enlist in the U.S. Armed Forces.
One ASVAB sub-measure, the Armed Forces Qualification Test (AFQT)--which is just a separate analysis of the same tests that focuses only on four of the subtests--is also population-referenced, but its score from 1-99 is a percentile score. This means that if you score a 73, you scored as well as or higher than 73% of test-takers in the national sample.