These are sections, or sub-tests, in the ASVAB:  Word Knowledge (WK), Paragraph Comprehension (PC), Arithmetic Reasoning (AR), Mathematics Knowledge (MK), General Science (GS), Mechanical Comprehension (MC), Electronics Information (EI), and Assembling Objects (AO), Auto & Shop Information (AS):  * AI and SI are administered as separate tests in the CAT-ASVAB (computerized version), but combined into one single score (labeled AS).
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.
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.
As a general rule of thumb, anything over an 85 on the ASVAB will qualify you for nearly any position in the armed forces. But there are slight breakdowns within each score. For example, in order to qualify for Surveillance and Communications (SC) in the Army, Word Knowledge, Paragraph Comprehension, Arithmetic Reasoning, Auto & Shop and Mechanical Comprehension all require high marks. Though scoring an 85 or above would guarantee you scored in a high enough percentile to qualify for SC.

In exchange for a service commitment, the Reserve Officers' Training Corps (ROTC) program provides you with money for college while you're in school. You must take one military science course along with your other college courses and, upon graduation, enter the service as a commissioned officer. (There is no military commitment for the first year in ROTC, allowing you to pursue ROTC on a trial basis to see if ROTC is for you.) Full ROTC scholarships pay for almost all tuition, fees and books charges for four years of college. ROTC scholarships also come in one, two and three-year lengths. For more information, call 1-800-USA-ROTC (Army), 1-800-USA-NAVY (Navy), 1-866-423-7682 (Air Force) and 1-800-MARINES (Marines).
The questions that have a tendency to arise rather quickly are something along the lines of “why is this test so important?” and “What is the overall purpose of this test?” Well, first it is important to define the actual test and to assess the colorful history of the test. The Armed Services Vocational Aptitude Battery test (ASVAB) is a test that was officially formatted in 1968 with the intention of mentally preparing soldiers with knowledge that identifies with the following:
The ASVAB is a timed test that measures your skills in a number of different areas. You complete questions that reveal your skills in paragraph comprehension, word knowledge, arithmetic reasoning and mathematics knowledge. These are basic skills that you will need as a member of the U.S. military. The score you receive on the ASVAB is factored into your Armed Forces Qualifying Test (AFQT) score. This score is used to figure out whether you qualify to enlist in the armed services.
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.