Numbers in a group together may be called a series or set of numbers. If the order in which they occur is significant then they may be called a sequence of numbers. 1, 4, 9, 16, 25 is a sequence of numbers, for example — it represents the numbers 1 to 5 squared.

1, 3, 5, 7 ... = odd numbers; 2, 4, 6, 8 ... = even numbers; 2, 3, 5, 7, 11 ... prime numbers. The highest number in a group is the maximum and the lowest is the minimum.

An approximate number is one which is roughly correct but is not the precise or exact number. Look at the figures and work out in your head what the approximate answer is likely to be. Then use a calculator to find the exact number.

An aggregate is a number reached by totalling a set of numbers = the total. The average mark achieved in the exam is calculated by taking the aggregate of all the marks and dividing by the number of exam entries.

A discrete number or unit is something which is separate and cannot be divided into smaller numbers or units of the same thing. The opposite of discrete is continuous.

A constant number or quantity is one that does not change. In the experiment we varied [changed] the amount of water in the beaker but kept the amount of salt added constant.

A random number is one chosen by chance, i.e. it is not predictable.