Mathematics key terms

Numbers written differently but having exactly the same value, such as $\frac12$, $0.5$ and $$.

The range containing every possible original value that could have produced a stated rounded value.

A value close to the exact answer, found using suitable known values or approximations.

A straight line drawn to represent the overall trend of the points on a scatter graph.

Finding the numerical value of an expression after values have been substituted.

A judgement about whether a result is reasonable and appropriate, based on its size, sign, units and context.

A whole number that is divisible by 2, including zero and negative whole numbers.

An event with an equal chance of happening or not happening; its probability is 0.5.

A result or group of results whose probability is being considered.

A value written without rounding or approximation, such as a fraction representing an infinite recurring decimal precisely.

A trigonometric ratio written without rounding, usually as an integer, fraction or surd.

A value written without rounding or approximation, such as a simplified fraction rather than a rounded decimal.

The rate used to convert an amount in one currency into an equivalent amount in another currency.

A point represented by an open circle because its value is not part of the solution set.

A value that a variable cannot take because it would make an original denominator zero or make another operation undefined.

A set of outcomes or events that covers every possible result of a trial.

A set of outcomes or events that covers every possible result, so at least one must occur.

To remove brackets by multiplying the term outside by every term inside.

The number of occurrences predicted for an event over a stated number of trials, found from probability multiplied by the number of trials.

The expected number of occurrences is the probability of an event multiplied by the number of trials; it describes a long-run average, not a guaranteed count.

The raised integer $n$ in $10^n$, showing how many factors of 10 are involved or, equivalently, how far the decimal point moves.

A graph that falls because each increase of 1 in $x$ multiplies the output by a constant between 0 and 1.

A function in which the variable appears as a power, such as $y=k^x$, where the base $k$ is a positive constant.

A graph that rises because each increase of 1 in $x$ multiplies the output by a constant greater than 1.

A relationship in which equal changes in the input repeatedly multiply the output by the same factor, modelled by a function such as $y=ab^x$.

The small raised number in a power that states how many copies of the base are multiplied; in $4^3$, the exponent is 3.

A combination of numbers, variables and operations that represents a value but does not state that two quantities are equal.

An angle outside a polygon between one side and the extension of an adjacent side.

A value estimated beyond the range of the available plotted or tabulated values.

A flat part of the surface of a 3D shape. Each face is a two-dimensional shape.