Is a calculator allowed on the OAR?

No. Calculators are not allowed on any part of the OAR, including the Math Skills Test. You work on scratch paper, so fast, accurate arithmetic saves time on every math question.

How can I get faster at mental math?

Practice a little every day rather than a lot once. Learn your times tables to 15 and squares to 20 cold, convert between fractions, decimals and percents without thinking, and use shortcuts such as finding 10% first and building other percents from it.

How should I type fractions in the drill?

Type a slash: 3/4. Mixed numbers work with a space (1 1/2), and so does the equivalent decimal (0.75). Answers don’t need to be in lowest terms: 6/8 counts as 3/4.

Free tool · OAR Math Skills

No-calculator math drill

Calculators aren’t allowed on the OAR. Build speed with timed rounds of arithmetic, fractions, percents and exponents, and see your pace per question.

Topics

Round length

Pick at least one topic. Fractions can be typed as 3/4, 1 1/2 or 0.75.

Warm-up set

Twelve problems to try on paper. Open each one to check your answer.

1.2/4 + 2/8Answer
= 3/4
2.2⁶Answer
= 64
3.177 + 574Answer
= 751
4.276 + 328Answer
= 604
5.27 ÷ 3 + 2²Answer
= 13
6.(15 + 8) × 4 − 6Answer
= 86
7.23 × 13Answer
= 299
8.12 ÷ 4 + 2²Answer
= 7
9.7/12 + 3/8Answer
= 23/24
10.(4 + 9) × 8 − 6Answer
= 98
11.288 ÷ 9Answer
= 32
12.√121Answer
= 11

Why practice without a calculator

The OAR doesn’t allow calculators, and most Math Skills questions end in a calculation: a percent of a total, a fraction of a tank, an average. If the arithmetic is slow or shaky, you lose time on every question even when you know the method. A few short rounds a day fix that faster than anything else.

What the drill covers

Add and subtract three-digit numbers.
Multiply and divide: two-digit by one-digit, teens by teens, and exact division.
Fractions: add, subtract, multiply and divide with common denominators up to 12.
Percents: 5% to 150% of round numbers.
Exponents and roots: squares to 20², cubes to 6³, powers of 2 and perfect-square roots.
Order of operations: multiplication before addition, parentheses first.

Shortcuts that save time

For percents, find 10% (move the decimal point) and build from it: 15% = 10% + 5%, 30% = 3 × 10%.
x% of y = y% of x: 8% of 50 is the same as 50% of 8, which is 4.
To multiply by 5, multiply by 10 and halve. To multiply by 25, multiply by 100 and divide by 4.
Learn the common fraction–decimal pairs: 1/8 = 0.125, 1/6 ≈ 0.167, 1/3 ≈ 0.333, 3/8 = 0.375, 5/8 = 0.625.

When you are ready for full word problems, take the OAR math practice test, and keep theformula sheet nearby.

Test yourself: an OAR-style question

On a budget pie chart, fuel costs take up a 120-degree slice. What percent of the budget is fuel?

Show answer

C. 33%

A full circle is 360°, so 120 ÷ 360 = 1/3, which is about 33%. Knowing that 1/3 ≈ 33% and 1/8 = 12.5% by heart saves a calculation.

Questions like this come up on the Math Skills section of the OAR. The 2,604 questions in the app each come with a written explanation.

FAQ

Is a calculator allowed on the OAR?: No. Calculators are not allowed on any part of the OAR, including the Math Skills Test. You work on scratch paper, so fast, accurate arithmetic saves time on every math question.
How can I get faster at mental math?: Practice a little every day rather than a lot once. Learn your times tables to 15 and squares to 20 cold, convert between fractions, decimals and percents without thinking, and use shortcuts such as finding 10% first and building other percents from it.
How should I type fractions in the drill?: Type a slash: 3/4. Mixed numbers work with a space (1 1/2), and so does the equivalent decimal (0.75). Answers don’t need to be in lowest terms: 6/8 counts as 3/4.

Sources

Naval Aerospace Medical Institute. ASTB-E Frequently Asked Questions

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