PIPEPREP AI
28 questions · ~21 min

Numerical Computation: The GAN Aptitude Test Section, Explained

Numerical Computation is 28 questions of pure arithmetic with no calculator — fractions, decimals, percentages, and the conversions between them. There is no word-problem wrapper here; it is the raw skill, tested for speed.

Questions
28
Time
~21 min
Calculator
Not allowed

That is about 45 seconds per question. This section is one of six on the battery, which runs about 140 questions in roughly two hours — see the full GAN aptitude test breakdown for how the whole thing fits together.

What this section measures

Whether you can do trade arithmetic by hand at working speed. Pipe work runs on fractions of an inch, and a fitter who needs a phone to add 5/8 and 3/16 is slow on the floor.

Together with Problem Solving, this is 63 of roughly 140 questions — nearly half the battery is arithmetic. It is the highest-leverage section to train, and the one where unprepared applicants lose the most ground.

How to train it

Rebuild fraction fluency first

Adding and subtracting unlike fractions, converting mixed numbers to improper fractions and back, and multiplying and dividing fractions are the four operations this section lives on. If those are rusty, nothing else you study matters as much. Twenty minutes a day for two weeks is usually enough to make them automatic again.

Memorise the eighths and sixteenths as decimals

Know 1/16 = 0.0625, 1/8 = 0.125, 3/16 = 0.1875, 1/4 = 0.25, 5/16 = 0.3125, 3/8 = 0.375, 1/2 = 0.5 and their partners without thinking. Half the conversion questions become instant recall instead of long division, and you get the time back on the harder items.

Cancel before you multiply

When multiplying fractions, divide out common factors across the numerators and denominators first. 5/6 x 9/10 becomes 1/2 x 3/2 after cancelling, which you can do in your head — multiplying straight across gives 45/60 and then makes you reduce a larger number under time pressure.

Estimate as a check, not as a method

Before you commit, ask whether the answer is roughly the size it should be. Two-thirds of something must be less than the something. A 15% increase must be a little more than the original. This catches decimal-place slips, which are the single most common arithmetic error on a timed no-calculator test.

Where applicants lose points

  • Decimal-point placement when multiplying decimals — 1.4 x 0.05 is 0.07, not 0.7.
  • Reducing incorrectly under time pressure, or forgetting to reduce when the answer choices are all in lowest terms.
  • Reaching for a calculator habit that is not there. Practise every drill by hand or you will train the wrong reflex.

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Frequently asked

Can I use a calculator on the GAN aptitude test?

No. No calculator is permitted on any section, which is precisely why fraction and decimal fluency by hand is the highest-value thing to train.

What kind of math is on the UA aptitude test?

Arithmetic, not advanced math. Fractions, decimals, percentages, ratios and basic algebra. There is no trigonometry, no calculus, and no geometry proof work.

How much of the test is math?

Numerical Computation (28), Numerical Reasoning (10) and Problem Solving (35) together are 73 of roughly 140 questions — a little over half the battery.

The other five sections

Ready to sit the whole thing? Take a free full-length practice test in the GAN format — timed sections, no calculator, instant scoring.

Drill Computation until it is your best section

Reading about a section and scoring on it are different things. The app has ten full-length timed batteries plus dedicated computation drills, so test day is your eleventh run at it, not your first.

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