Symbols used to show items that should be treated as together or as having priority. In arithmetic and algebra, operations within brackets are given priority. Example: 2 x (3 + 4) = 2 x 7 = 14 whereas 2 x 3 + 4 = 6 + 4 = 10.

One way to simplify a fraction. The numerator and denominator are divided by a common factor. Also to ’reduce’ a fraction. Example: to simplify 6/16 the fraction is 'cancelled down' when the numerator and denominator are divided by 5 to give 1/3.

Volume, i.e. a measure of three-dimensional space, applied to liquids, materials that can be poured or the space within containers. Units include cubic centimetres and litres - a

A system used to define the position of a point in two-dimensional and three-dimensional space. Two axes at right angles to each other are used to define the position of a point in a plane. The convention is to label the horizontal axis as the x-axis and the vertical axis as the y-axis. In this case, the origin is the intersection of the axes. The ordered pair of numbers (x, y) that defines the position of a point is the coordinate pair. Each of the numbers is a co-ordinate. The numbers are also known as Cartesian co-ordinates, after the French mathematician, René Descartes.

Data arising from measurements taken on a categorical (unordered discrete) variable. Examples: pupils\' favourite colours; states of matter- solids, liquids, gases, gels etc; nutrient groups in foods - carbohydrates, proteins, fats etc; settlement types - hamlet, village, town, city etc; and types of land use - offices, industry, shops, open space, residential etc.

Prefix meaning one-hundredth (of)

Symbol: cl. A unit of volume equivalent to one-hundredth of a litre.

Symbol: cm. A unit of linear measure, one hundredth of a metre.

The middle point.

A straight line segment joining two points on a circle or other curve.