# Glossary (Version 8.4)

Numerical variables are variables whose values are numbers, and for which arithmetic processes such as adding and subtracting, or calculating an average, make sense.

A discrete numerical variable is a numerical variable, each of whose possible values is separated from the next by a definite 'gap'. The most common numerical variables have the counting numbers 0,1,2,3,… as possible values. Others are prices, measured in dollars and cents.

Examples include the number of children in a family or the number of days in a month.

Variable (algebra): A variable in algebra is a symbol, such as x, y or z used to represent an unspecified member of some set. For example, the variable x could represent an unspecified real number. Variable (statistics): A variable in statistics is something measurable or observable that is expected to either change over time or between individual observations.

Examples of variables in statistics include the age of students, their hair colour or a playing field’s length or its shape.​

a word class that describes a kind of situation such as a happening (for example, 'climbed' in 'She climbed the ladder') or a state (for example, 'is' in 'The koala is an Australian mammal').

consists of a main verb, alone or preceded by one or more auxiliary or modal verbs as modifiers. For example, verb groups/phrases: create tense, as in 'He [was happy]', 'She [is working] at home', 'I [have seen] him before'; express modality using modal verbs such as 'can', 'may', 'must', 'will', 'shall' and so on, as in 'You [must be] mad', 'He [will have arrived] by now', 'She [may know] them'; and create passive voice, as in 'A photo [was taken]'.

a word class that describes a kind of situation such as a happening (for example, 'climbed' in 'She climbed the ladder') or a state (for example, 'is' in 'The koala is an Australian mammal').

observe with purpose, understanding and critical awareness. Some students participate in viewing activities by listening to an adult or peer describing the visual features of text, diagrams, pictures and multimedia

in English grammar voice is used to describe the contrast between such pairs of clauses as 'The dog bit me' (active voice) and 'I was bitten by the dog' (passive voice). Active and passive clauses differ in the way participant roles are associated with grammatical functions. In clauses expressing actions, like the above examples, the subject of the active ('the dog') has the role of actor, and the object ('me') the role of patient; whereas, in the passive, the subject ('I') has the role of patient and the object of the preposition by ('the dog') the role of actor. In clauses that describe situations other than actions, such as 'Everyone admired the minister' and 'The minister was admired by everyone', the same grammatical difference is found, so that the object of the active ('the minister') corresponds to the subject of the passive; and the subject of the active ('everyone') corresponds to the object of the preposition 'by'. And in the literary sense, it can be used to refer to the nature of the voice projected in a text by an author (for example, 'authorial voice' in a literary text or 'expert voice' in an exposition).

The volume of a solid region is a measure of the size of a region.

For a rectangular prism, Volume = Length × Width × Height