Edexcel GCSE Mathematics key terms

One of the four regions formed by the coordinate axes.

An equation containing a squared variable as its highest power; its graph may be a parabola.

An expression whose highest power of the variable is 2, such as $3x^2-8x+4$.

A function whose highest power of $x$ is $2$; its graph is a parabola.

An inequality involving a squared variable, such as $x^2-x-2>0$, whose solution can be a range of values.

A sequence with a constant, non-zero second difference and an nth-term expression of the form $an^2+bn+c$, where $a\ne0$.

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 $Q_3$.

The number or expression beneath a root sign; in $\sqrt{12}$, the radicand is $12$.

The distance from the centre of a circle to its circumference.

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

Differences between experimental results caused naturally by chance.

The difference between the greatest and least values in a data set.

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

How much one quantity changes for each unit change in another quantity.

The amount earned per unit of time, such as pounds per hour.

A comparison showing the relative sizes of quantities in a stated order, written in a form such as $a:b$.

To remove a surd from a denominator without changing the value of the expression.

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 numbers in a ratio; it represents a share of the comparison rather than necessarily one object.

A comparison of drawing length with corresponding real length, with both lengths first expressed in the same unit.

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

The reciprocal of a non-zero quantity $x$, written $\frac{1}{x}$. Multiplying $x$ by its reciprocal gives $1$.

A function in which the output is the reciprocal of the non-zero input; for example, $y=1/x$.

A relationship in which one variable is proportional to the reciprocal of another; multiplying the two variables gives a constant.

A quadrilateral with four right angles.

A rule that defines a term using one or more preceding terms.

The digit or block of digits that repeats indefinitely in a recurring decimal.