GNFS Aptitude Test key terms

The size of a rise in a value expressed as a share of the original value, calculated by dividing the amount of increase by the starting figure and multiplying by 100.

The size of a fall in a value expressed as a share of the original value, found by dividing the amount of decrease by the starting figure and multiplying by 100.

A comparison of two or more quantities showing how many times one contains another, often written with a colon such as 3:2 and reducible like a fraction.

A statement that two ratios are equal, allowing an unknown quantity to be found when the other three parts of the comparison are known.

A technique that first finds the value of one unit by division, then multiplies to obtain the value of the required number of units.

A calculation that recovers an original amount before a percentage change, by dividing the final value by one plus or minus the rate expressed as a decimal.

How quickly one quantity alters relative to another, usually time, computed as the difference in value divided by the difference in the reference quantity.

Total distance travelled divided by total time taken, which differs from the mean of separate speeds whenever the time spent at each speed is unequal.

A mean in which each value contributes in proportion to an assigned weight, so larger-weight items influence the result more than smaller-weight items.

The arithmetic average, obtained by adding all values in a set and dividing the total by the number of values present.

The middle value of a set arranged in order, or the average of the two middle values when the set contains an even number of items.

The difference between the largest and smallest values in a data set, giving a simple but easily distorted measure of how spread out the values are.

A measure of how far values typically sit from their mean, calculated from the square root of the average squared deviation.

The number by which every length in a figure is multiplied to produce a similar figure, with areas changing by the square of that number.

Shapes with identical angles whose corresponding sides are in the same ratio, so one is an enlargement of the other without distortion.

An ordered list of numbers generated by a rule, such as repeated addition, multiplication, or alternating operations, where the rule must be inferred to continue the list.

The sequence of gaps between consecutive terms in a number series; constant gaps indicate a linear rule, while changing gaps may reveal a second-level pattern.

The underlying operation or combination of operations that produces each term of a series from earlier terms, allowing prediction of missing or subsequent values.

A conclusion drawn from stated evidence rather than stated outright, valid only when the passage logically requires it and not merely permits it.

An unstated premise that must be true for an argument's conclusion to follow from its evidence, even though the author never says it directly.

The main claim an argument asks the reader to accept, supported by the other statements, which serve as premises or evidence.

A statement offered as evidence or a reason within an argument, intended to support the conclusion rather than to be proved by it.

A response that makes the link between an argument's evidence and conclusion more credible, often by supplying an additional supporting fact or removing a rival explanation.

A response that reduces support for an argument's conclusion, typically by offering an alternative cause, a counterexample, or evidence that a required assumption fails.

The central point a passage is written to convey, broad enough to cover the whole text yet specific enough to exclude minor supporting details.

The attitude an author conveys toward the subject, such as critical, neutral, cautious, or enthusiastic, signalled by word choice rather than stated directly.

The emotional or evaluative association a word carries beyond its literal meaning, which can shift how a reader judges the same underlying fact.

The literal, dictionary meaning of a word, independent of the feelings or associations it may trigger in a particular context.

A comparison asserting that one pair of words shares a relationship identical to that of a second pair, such as part to whole or cause to effect.

A word with a meaning close to that of another word, though the two may differ in formality, intensity, or the contexts in which they naturally appear.

A word expressing a meaning opposite to another word, ranging from strict logical opposites to graded pairs with intermediate positions.

Deriving a necessary conclusion from given statements by applying rules of logic, so that if the premises are true the conclusion cannot be false.

A formal argument with two premises sharing a common term and a conclusion linking the remaining terms, assessed for validity rather than factual truth.

The property of an argument whose structure guarantees that true premises produce a true conclusion, regardless of whether those premises are actually true.

The logically equivalent form of a conditional statement obtained by negating both parts and swapping them, so 'if P then Q' becomes 'if not Q then not P'.

The result of swapping the two parts of a conditional statement; unlike the contrapositive, the converse is not automatically equivalent to the original.

A puzzle presenting a grid of figures governed by rules across rows and columns, where the missing cell must be supplied by identifying those rules.

A sequence of shapes that changes according to consistent rules such as rotation, shading, or added elements, requiring the next figure to be predicted.

A rule in which a shape turns by a fixed angle at each step, often clockwise or anticlockwise, sometimes combined with reflection or size change.

Reading values, trends, and comparisons from tables, charts, or graphs, then performing the arithmetic needed to answer a question about them.

The horizontal or vertical reference line of a graph that carries its scale, whose units and starting value must be checked before any value is read.

A misleading effect created when a graph's axis does not start at zero or uses uneven intervals, making differences look larger or smaller than they are.

The general direction in which data moves over a period, such as rising, falling, or flat, distinguished from short-term fluctuations around that direction.

Estimating values beyond the range of observed data by continuing an established pattern, a method that grows less reliable the further it projects.

Estimating an unknown value that lies between two known data points, typically by assuming a steady change across the intervening interval.

A mistake made when copying figures or text from a source, such as swapping digits or dropping a decimal point, which silently corrupts later calculations.

Writing the digits of a number in the wrong order, for example recording 3,417 as 3,147, a common slip that survives casual checking.

Checking text or tables character by character against the original to catch errors in spelling, punctuation, numbering, and formatting before the work is submitted.

The agreed sequence for evaluating expressions, giving brackets first, then powers, then multiplication and division, then addition and subtraction, working left to right within a level.

Producing a quick approximate answer by rounding values to convenient figures, useful for judging whether an exact calculation is plausible.

Replacing a number by a nearby value with fewer significant digits, following a stated level of accuracy and a rule for handling the halfway digit.

The digits of a number that carry meaningful information about its precision, counted from the first non-zero digit and including trailing zeros only where justified.

Ensuring all quantities in a calculation share the same units, converting where necessary, so that the result is meaningful rather than a mix of incompatible measures.

Verifying that an answer carries the expected unit, such as speed in kilometres per hour rather than hours per kilometre, as a quick test of whether a calculation is set up correctly.

A table that scores options against weighted criteria, making trade-offs explicit so that a choice can be compared and defended systematically.

The sacrifice of one benefit to gain another, arising whenever options cannot maximise every desirable outcome at the same time.

The value of the best alternative given up when a choice is made, which belongs in any sound comparison of competing options.

A circumstance whose presence guarantees that a stated outcome occurs, though the outcome may still occur through other means when it is absent.

A requirement that must hold for a stated outcome to occur, so its absence rules the outcome out even though its presence does not guarantee it.