Take as many practice math tests as possible. Time yourself to mimic the actual test-taking experience as closely as possible. Memorize the order of operations in math (parentheses, exponents, multiply, divide, add, subtract); it may be helpful to use a mnemonic device for this, such as "Please excuse my dear Aunt Sally." You should also memorize common mathematical formulas before the test, such as the formulas for perimeter, geometric areas and the Pythagorean theorem.
Most of the ASVAB math questions are based on relatively basic mathematical operations, but it's important to review even seemingly easy material in case you're no longer familiar with it. Review algebra, fractions, and factorials to reacquaint yourself with basic algebraic equations. Spend a significant portion of your study time reviewing geometry; data for circles, squares, triangles and cubes is like to figure prominently on the ASVAB. You should also review different kinds of numbers; for example, real, rational, irrational, whole, natural and composite. For the arithmetic reasoning section, you'll need to be familiar with rations, percentages, proportions and unit conversions.
There are two math sections on the ASVAB; arithmetic reasoning and mathematics knowledge. For the arithmetic reasoning section, you'll have 36 minutes to answer 30 questions. For mathematics knowledge, you'll need to answer 25 questions in 24 minutes. The arithmetic reasoning section features word problems, so be prepared to read lengthy questions and quickly extract the actual question. The mathematics reasoning section is generally more straightforward, so always check your answers for accuracy before moving on. Neither section, however, is more valuable than the other. If you find that you have a natural proclivity for word problems, for example, don't worry about a weaker score on the other section.
Don't answer a question without first being completely sure of what it is asking. Read questions quickly and discard any superfluous information right away. Quickly determine whether the question can be answered within a minute; if it cannot, skip it and and come back later if you have time. If you run into several questions that seem too long, look for a shortcut to the answer; sometimes, the best-known way to answer the question can be the most time-consuming. For multiple-choice questions, try substituting each possible answer to find the correct one. Use the scratch paper provided; trying to quickly do long equations in your head makes you more susceptible to errors.