Tips for Guessing on the Arithmetic Reasoning Subtest of the ASVAB

By Rod Powers

Guessing wrong on any of the ASVAB subtests doesn’t count against you (unless you guess incorrectly on a bunch of questions in a row at the end of the subtest when taking the CAT-ASVAB). If you don’t guess, your chances of getting that answer right are zero, but if you take a shot at it, your chances increase to 25%, or 1 in 4. Eliminate two wrong answers, and you have a 50-50 shot.

If you’re taking the paper version of the ASVAB, you can always skip the tough questions and come back to them after you’ve finished the easier ones. If you’re taking the computerized version of the ASVAB, the software won’t let you skip questions, so you need to make your guess right then and there.

If you’re taking the paper version of the test and elect to skip questions until later, make sure you mark the next answer in the correct space on the answer sheet. Otherwise, you may wind up wearing out the eraser on your pencil when you discover your error at the end of the test. Or even worse, you may not notice the error and wind up getting several answers wrong because you mismarked your answer sheet.

Using the process of elimination

Guessing doesn’t always mean “pick an answer, any answer.” You can increase your chances of picking the right answer by eliminating answers that can’t be right. To eliminate some obvious wrong answers, you can do the following:

  • Make sure the answer is realistic in relation to the question asked. For example, if a question asks you how much water would be required to fill a child’s wading pool, 17,000 gallons isn’t a realistic answer. You can save time by eliminating this potential answer choice immediately.

  • Pay attention to units of measurement. If a question asks how many feet of rope you’ll need, answer choices listed in inches or cubic feet are probably incorrect.

  • Consider easier answer choices first. Remember, you’re not allowed to use a calculator on the ASVAB, so math answers that you’d arrive at by using complicated formulas are probably not correct.

Solving what you can and guessing the rest

Sometimes you may know how to solve part of a problem but not all of it. If you don’t know how to do all the calculations — or don’t have time for them — don’t give up. You can still narrow down your choices by doing what you can. Here’s how partially solving problems can help:

  • When adding mixed numbers (a whole number and a fraction), add the whole-number parts first; then immediately eliminate answer choices that are too low. Or when adding lengths, add full feet first and cross off choices that are too small, even before considering the inches.

  • Multiply just the last digits and cross off all answers that don’t end in the right numbers (assuming the answers aren’t rounded).

Making use of the answer choices

If you’re stuck on a particular problem, sometimes plugging possible answers into an equation can help you find the right answer. Here’s how using the answer choices can improve your guessing:

  • Plug in each remaining answer choice until you get the right answer. Plugging in all the answer choices is time-consuming, so make sure you eliminate obviously wrong choices first.

  • Estimate and plug in numbers that involve easy mental calculations. For instance, if Choice (A) is 9 and Choice (B) is 12, plug in 10 and solve the equation in your head. Think about whether the right answer has to be higher or lower than 10, and choose from there.

  • Using a little logic, do calculations with an obviously wrong answer choice. Sometimes a wrong answer choice — especially one that differs drastically from the other answers — represents an intermediate step in the calculations, so you can use it to solve the problem. For instance, take this example:

A security guard walks the equivalent of six city blocks when he makes a circuit around the building. If he walks at a pace of eight city blocks every 30 minutes, how long will it take him to complete a circuit around the building, assuming he doesn’t run into any thieves?

  • (A) 20.00 minutes

  • (B) 3.75 minutes

  • (C) 22.50 minutes

  • (D) 24.00 minutes

Choice (B) is obviously way too low to be the right answer, but it would be a logical guess for the security guard’s rate for a single lap. Multiply 3.75 minutes/block by 6 blocks, and you probably have a good candidate for the right answer — 22.50 minutes, Choice (C).