The OAR, or Officer Aptitude Rating, is the portion of the ASTB-E that some non-aviation officer candidates may take instead of the full aviation test battery. Official Navy Medicine information describes the OAR portion as consisting of the Math Skills Test, Reading Comprehension Test, and Mechanical Comprehension Test. This guide focuses on the math portion: what it measures, how to diagnose weak areas, and how to study without wasting time on topics that do not move your score.
ViewMath is an independent publisher and is not affiliated with or endorsed by the U.S. Navy, Marine Corps, Coast Guard, NMOTC, or the ASTB-E/OAR program. For official details, use the ASTB-E FAQ, the NMOTC Operational Psychology ASTB-E overview, and your recruiter.
OAR Format: What Is Officially Confirmed
The official FAQ says the OAR can take anywhere from 1 to 2 hours in APEX, while the full ASTB-E can take longer. NMOTC also describes APEX as computer-adaptive, which means examinees may see different combinations of items. Because the public official material is an overview rather than a complete released-question blueprint, the safest prep strategy is to master the underlying math skills and practice under time pressure.
| OAR Subtest | What It Measures |
|---|---|
| Math Skills Test | Arithmetic, algebra, geometry, equations, word problems, rates, and probability-type reasoning. |
| Reading Comprehension Test | Extracting meaning from written passages and drawing conclusions from the passage itself. |
| Mechanical Comprehension Test | Understanding practical mechanical relationships, fluids, pressure, velocity, engines, electricity, gears, and simple machines. |
What OAR Math Covers
The official overview says the math skills assessed include arithmetic and algebra, with some geometry. It mentions equations, word problems, variables, time and distance, simple probabilities, fractions, roots, exponents, and calculations involving angles, areas, and perimeters. For practical study, group the content into five buckets:
- Arithmetic: integer operations, fractions, decimals, percents, ratios, rates, and estimation.
- Algebra: simplifying expressions, solving equations and inequalities, translating word problems, and linear relationships.
- Geometry: perimeter, area, volume, angles, the Pythagorean theorem, and coordinate basics.
- Data and probability: averages, tables, graphs, simple probability, and proportional comparisons.
- Timed problem solving: choosing a method quickly, simplifying before calculating, and checking reasonableness.
OAR Math Diagnostic
Try these without a calculator. If you miss a problem, mark the topic and do a short repair set before taking another mixed quiz.
- What is 18% of 250?
- Simplify: 3/4 + 5/8.
- Solve: 4x – 9 = 31.
- A boat travels 180 miles in 4 hours. At the same rate, how far does it travel in 7 hours?
- A right triangle has legs of 8 and 15. What is the hypotenuse?
- A data set is 6, 8, 8, 10, 13. Find the mean and median.
- If 5 machines make 120 parts in 3 hours, how many parts does one machine make per hour?
- Simplify: 2(3x – 5) + 4x.
- A rectangle has perimeter 46 and length 15. What is its width?
- What is the probability of rolling an even number on a fair six-sided die?
Solutions and Fast Methods
- 45. 10% is 25, 8% is 20, so 18% is 45.
- 11/8 or 1 3/8. Convert 3/4 to 6/8, then add 6/8 + 5/8.
- x = 10. Add 9 to get 4x = 40; divide by 4.
- 315 miles. The rate is 45 miles per hour; 45 x 7 = 315.
- 17. Use the 8-15-17 triangle or compute √(64 + 225).
- Mean = 9 and median = 8. The sum is 45 and there are 5 values.
- 8 parts per machine per hour. 120 / 5 = 24 parts per machine in 3 hours; 24 / 3 = 8.
- 10x – 10. Distribute first: 6x – 10 + 4x.
- 8. Perimeter gives 2L + 2W = 46, so 30 + 2W = 46.
- 1/2. Even outcomes are 2, 4, and 6, so 3 out of 6.
Common OAR Math Mistakes
- Doing arithmetic too late: Set up the relationship first. Many rate and work problems are easier after writing units.
- Not simplifying fractions: Reducing before multiplying can save time and reduce mistakes.
- Trusting a memorized formula without checking units: Area, perimeter, volume, speed, and work-rate problems all use different units.
- Reading too fast: The difference between “how many remain” and “how many were used” changes the operation.
- Only drilling hard problems: Timed tests punish slow basic arithmetic. Keep fundamentals sharp.
4-Week OAR Math Prep Plan
| Week | Focus | Daily Work |
|---|---|---|
| 1 | Arithmetic foundations | Fractions, decimals, percents, ratios, unit rates, and mental math. |
| 2 | Algebra | Equations, inequalities, expressions, word-problem setup, and linear relationships. |
| 3 | Geometry and data | Formula review, Pythagorean theorem, area, volume, tables, averages, and probability. |
| 4 | Mixed timed review | Short no-calculator sets, full mixed practice, pacing checks, and error-log repair. |
How to Practice More Efficiently
Use a two-column error log: one column for the problem type and one column for the fix. “Algebra sign error” is more useful than “missed #8.” Every three study sessions, retake only the missed-topic problems. If accuracy is above 85 percent but speed is slow, switch to short timed sets. If speed is fine but accuracy is below 80 percent, slow down and rebuild the weakest topics before taking another practice test.
ViewMath OAR Math Resources
ViewMath OAR resources focus on the math content that supports the Math Skills Test: arithmetic, algebra, geometry, data analysis, formulas, and no-calculator practice. Start with the ViewMath OAR Math collection. Choose a study guide if you need instruction, a workbook if you need targeted repetition, and a practice-test book after your error log shows that the core topics are under control.
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