Mathematics key terms

An inequality containing a squared variable, such as x² − 4 < 0.

A sequence whose terms are generated by a rule involving the square of the position; its second differences are constant.

A four-sided polygon.

One of the values that divides ordered data into four approximately equal parts. The lower quartile is $Q_1$ and the upper quartile is $Q_3$.

A set of questions used to collect information from people.

The result of dividing one quantity by another.

The number or expression beneath a root sign; in $5\sqrt7$, the radicand is $7$.

A straight line segment from the centre of a circle to its circumference, or its length.

A process is random if its individual result cannot be predicted with certainty, even when the chances of its possible results are known.

A possible result whose occurrence is uncertain, such as getting heads on a coin toss.

An experiment with an unpredictable individual result, even if some results are more likely than others.

A process governed by chance, so its individual result cannot be predicted with certainty. Random outcomes need not be equally likely.

An outcome that cannot be predicted with certainty before a trial, even though probabilities may be known.

A sample selected by chance so that every member of the population has an equal probability of selection.

Differences between experimental results caused naturally by chance.

The set of possible output values of a function.

A comparison describing how much of one quantity there is per unit of another quantity, such as £12 per hour.

The change in the vertical quantity divided by the corresponding change in the horizontal quantity.

An amount paid for each unit of time worked, such as pounds per hour.

A comparison showing the relative sizes of two or more quantities in a stated order.

To rewrite a fraction with no surd in its denominator without changing its value.

Rewriting a fraction so that its denominator contains no surd while keeping its value unchanged.

A number that can be written as a fraction of two integers, with a non-zero denominator.

The colon used to separate the parts of a ratio; for example, $3:5$ is read as “three to five”.

One of the equal-sized units represented by the numbers in a ratio.

A comparison of a length on a drawing with the corresponding real length, expressed using the same units, such as 1 : 25 000.

A graph in which the variables represent measurable quantities from a situation, so the axes require labels and units.

A root that is a real number, so it can be represented on the number line. Negative numbers have real odd roots but no real even roots.

A graph that represents quantities from a practical situation, with each axis showing a variable and usually its unit.

To change the form of an equation without changing the relationship it represents.