Maths Terms for 11-13 Yr Olds

A measure of the average of a set of data, calculated by adding up all terms and dividing by the number of terms in the set. For example the mean of 3, 5, and 13 is the numbers added together (21) divided by the amount of numbers (3) which works out as 7.

The mean takes account of all values and finds the overall average. Finding the mean is the most common way of measuring a data set's average, but can be problematic if one or two anomalous (wrong) values are taken and skew the result.

The 'median' is the middle value in a data set when the set is arranged in order from smallest to largest. For example in 3, 4, 5, 6, 7, the median value is 5. For sets containing an even amount of numbers, the median is halfway between the central pair.

The median is another way of analysing a data set, and along with the mean and mode is another form of an 'average'. In some situations it would be more appropriate, such as when the highest and lowest values are expected to be large and inaccurate.

The most common value in a set of data. For example in 2, 3, 3, 3, 3, 2, the modal value would be 3. If no value is repeated, no mode exists.

In some situations the mode could be thought of as the most appropriate 'average' value for the data, e.g. in samples involving whole numbers or quantities (the mean, as opposed to mode, will usually give a decimal number).

1. In geometry, a plane figure in 2D composed of polygons which by folding and joining can form a 3D polyhedron.

2. Adjective meaning 'remaining after deductions'. Example: for businesses net profit is their profit after deducting all operating costs and expenses.

Any convention for recording mathematical ideas in writing and symbols. Example: Money is recorded using decimal notation e.g. £2.50.

A fixed point from which measurements are taken. See also Cartesian co-ordinate system. On a graph the origin is normally given by the point at which the x axis meets the y axis, at the co-ordinate (0,0).

A systematic arrangement of numbers, shapes, values or other objects according to a rule.

A fraction expressed as the number of parts per hundred and recorded using the notation %. Example: One half can be expressed as 50%; the whole can be expressed as 100%.

A format for representing statistical information using pictures. Suitable pictures, symbols or icons are used to represent objects. For large numbers one symbol may represent a number of objects and a part symbol then represents a rough proportion of the number.

Also known as pie graph. A form of presentation of statistical information - within a circle, sectors like the slices of a pie represent the quantities involved. The frequency or amount of each quantity is proportional to the angle at the centre of the circle.