Mathematics Oral Exam Questions and Answers
These mathematics oral exam questions and answers practice nine of the knowledge elements in General ACS subject AM.I.H, Mathematics. For O&P study, explain the operation, keep the units, and show how you checked the result.
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What should my answer explain?
Our study tip: say the method before the number. Name the operation, keep the units with every value, and finish by checking the result, for example by putting it back into the equation. The numbers below are the General handbook’s own worked examples; they practice mathematics and are not aircraft dimensions, repair limits, or operating settings.
FAA-S-ACS-1, p. 13 · AM.I.H: Mathematics
Which ACS elements do these questions practice?
The table maps each study prompt to its knowledge element. It is not a prediction of assigned test questions.
| ACS element | Study focus |
|---|---|
| AM.I.H.K8 | Scientific (exponential) notation, decimal notation, fractional notation, binary notation, and conversion between these various forms of numeric notation. |
| AM.I.H.K9 | Rounding numbers. |
| AM.I.H.K13 | Basic mathematic functions (addition, subtraction, multiplication, division). |
| AM.I.H.K5 | Proportion and percentage problems, including examples of where or how they may be used in relation to aircraft maintenance or system(s) operation. |
| AM.I.H.K4 | Ratio problems, including examples of where or how they may be used in relation to aircraft maintenance or system(s) operation. |
| AM.I.H.K6 | Algebraic operations, including examples of where or how they may be used in relation to aircraft maintenance. |
| AM.I.H.K10 | Powers and special powers. |
| AM.I.H.K1 | Areas of various geometrical shapes. |
| AM.I.H.K2 | Volumes of various geometrical shapes. |
Which oral exam questions can I practice?
These practice questions are built from ACS elements; they are not actual FAA test questions.
1. How do you convert 3/8 to a decimal?
ACS: AM.I.H.K8
Divide the numerator by the denominator: 3 ÷ 8 = 0.375. I can check the result by multiplying 0.375 by 8 to get 3.
FAA-H-8083-30B, General, p. 3-7
2. Round 3.7487 feet to the nearest thousandth. How do you decide?
ACS: AM.I.H.K9
The thousandths digit is 8, and the digit to its right is 7. Because 7 is 5 or greater, I round the 8 up to 9, so the answer is 3.749 feet. If that digit were less than 5, I would leave the 8 unchanged.
FAA-H-8083-30B, General, p. 3-6
3. How would you divide 0.144 by 0.12?
ACS: AM.I.H.K13
The divisor is a decimal, so I change it to a whole number first: move the decimal in 0.12 two places to the right to get 12, and move the decimal in 0.144 the same two places to get 14.4. Then 14.4 ÷ 12 = 1.2.
FAA-H-8083-30B, General, p. 3-6
4. Solve the proportion 65/80 = X/100.
ACS: AM.I.H.K5
Cross-multiply and divide: X = (65 × 100) ÷ 80 = 81.25. Substituting 81.25 back gives the same value for both ratios.
FAA-H-8083-30B, General, p. 3-8
5. Fifteen percent of a shipment of 80 lights is defective. How many lights is that?
ACS: AM.I.H.K5
Convert 15% to 0.15 and multiply by 80, giving 12 defective lights. As a proportion, 12/80 equals 15/100.
FAA-H-8083-30B, General, p. 3-10
6. A 10-tooth pinion drives a 40-tooth gear turning at 160 rpm. What is the pinion speed?
ACS: AM.I.H.K4
The pinion turns at 640 rpm: (40 × 160) ÷ 10. Gear speeds vary inversely with the tooth counts, so the smaller gear turns faster.
FAA-H-8083-30B, General, p. 3-8
7. How do you solve N + 17 = 59?
ACS: AM.I.H.K6
Subtract 17 from both sides, giving N = 42. I check the answer by putting 42 back into the equation: 42 + 17 = 59.
FAA-H-8083-30B, General, p. 3-16
8. What does two raised to the negative third power mean?
ACS: AM.I.H.K10
A number with a negative power equals its reciprocal with the same power made positive. So 2⁻³ = 1/(2 × 2 × 2) = 1/8, or 0.125.
FAA-H-8083-30B, General, p. 3-12
9. What is the cross-sectional area of a cylinder with a five-inch bore?
ACS: AM.I.H.K1
Use area = π × radius squared. The bore is the inside diameter, 5 inches, so the radius is 2.5 inches; using 3.1416 for π gives 3.1416 × 2.5² = 19.635 square inches.
FAA-H-8083-30B, General, p. 3-19
10. How much volume is in a rectangular space three feet long, two feet wide, and two feet high?
ACS: AM.I.H.K2
Multiply length by width by height: 3 × 2 × 2 = 12 cubic feet. All three dimensions are in feet, so the result is in cubic feet.
FAA-H-8083-30B, General, p. 3-21
How do I rehearse the answer out loud?
Read the question, put the answer aside, and give a connected explanation. Then compare your answer with the cited FAA page and repeat the prompt. This is our study routine, not an FAA scoring rule.
When a real task needs a calculation, take the values from the applicable manufacturer’s instructions and aircraft-specific data, not from these example numbers.
What else should I know?
Does rounding always increase the retained digit?
No. If the next digit is below 5, the retained digit stays as it is; if the next digit is 5 or more, increase it by one.
FAA-H-8083-30B, General, p. 3-6
What is a ratio?
A ratio is the comparison of two numbers or quantities. The same comparison can be written as a fraction, with a colon, or with the word “to.”
FAA-H-8083-30B, General, p. 3-7
What is a proportion?
A proportion is a statement of equality between two or more ratios. In a proportion, the product of the extremes equals the product of the means.
FAA-H-8083-30B, General, p. 3-8
How is 0.000000457 written in scientific notation?
The scientific-notation form is 4.57 × 10⁻⁷. The decimal moves seven places to the right to put it between the first and second significant digits, so the exponent is negative seven.
How can I rehearse the spoken answer?
DMEReady is an AI voice examiner for the A&P oral in your phone or computer browser. You answer out loud, and it asks follow-up questions the way a DME would. You can also rehearse an oral built from the ACS codes on your Airman Knowledge Test Report (AKTR). After each session, the report shows what you covered, what you missed, what a complete answer includes, and where to read in the FAA handbooks. You can save it as a PDF study sheet and share a result image that never shows your answers or name. The first drill is free, with no sign-up. DMEReady is an AI examiner, not a human DME. It is independent and is not affiliated with or endorsed by the FAA; it does not predict or guarantee results.
Start your free drillWhich guide should I read next?
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Which sources support these answers?
Sources were checked on October 18, 2026. Citations show the printed page; links target the corresponding PDF page.
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