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.
To be admitted to the ASVAB testing room you will need to show a valid id. It is also important to be on time (or early!) since you will be turned away if you show up after the scheduled start time. The ASVAB can be given via computer or pencil and paper.  If you are testing at a MEPS site you will take it on a computer.  The pencil and paper version is given at most MET sites.  The computer version of the test is given as a "computer adaptive test" (CAT) which means that the test will adapt based on the level of the individual test taker (e.g., if you answer many questions correctly, you may be shown fewer questions).
While you may want to get the ASVAB over with, it is important to give yourself enough time to prepare and practice for the ASVAB. Once you take the test you will have to wait 30 days before you are eligible to re-take the test if you got a non-passing score, or if you want a better grade. After you retake the test twice, you will need to wait for a 6 month time period before being able to take the test again. For this reason, it is important to pick an ASVAB test date that gives you plenty of time to practice and prepare for each section of the test.
Once the ASVAB is over, participants are given a score. This score is used by recruiters to determine which branch of the military would be a good fit for a given test-taker. The most important score for the ASVAB for military purposes is the AFQT score. The AFQT score looks at results from the following sections: Arithmetic Reasoning (AR), Math Knowledge (MK), and multiplies the Verbal Composite (VE) score by two. This is because the Verbal Composite Score is composed of both the Word Knowledge and the Paragraph Comprehension scores. Each branch of the military requires a different minimum AFQT score for its members. For the army and marines, this number is 31, for the navy 35, the air force 36, and the coast guard 45. Therefore, this test is a crucial part of any military career, and can determine potential jobs and advancement opportunities. Along with advancement opportunities come higher salaries and greater benefits, which makes the ASVAB an essential element for prospective military service personnel at any level.
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.