Maths Terms for 11-13 Yr Olds

A characteristic of a body, relating to the amount of matter within it. Mass differs from weight, the force with which a body is attracted towards the earth’s centre. Whereas, under certain conditions, a body can become weightless, mass is constant. In a constant gravitational field weight is proportional to mass.

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.

In the context of geometric figures this noun just means the process of measuring or calculating angles, lengths, areas and volumes.

Symbol: m. The base unit of length in SI ('Système International d.Unités' in French, also known as metric).

Units of measurement in the metric system. Metric units include the metre, centimetre, millimetre, kilometre, gram, kilogram, litre and millilitre. The metric system was developed in the 18th century in France. Most of the world now uses a modern form of metric units known as SI units (Système International d'Unités in French), especially in science and technology. Some exceptions exist, for example in the UK draught beer must be sold in pints, and speedometers must diplay miles per hour, which are imperial units.

An imperial measure of length. 1 mile = 1760 yards. Five miles is approximately 8 kilometres.

Prefix meaning 'one-thousandth'.

Symbol: ml. One thousandth of a litre.

Symbol: mm. One thousandth of a metre.

The name for the symbol -, which represents the operation of subtraction.

Unit of time. One-sixtieth of an hour. 1 minute = 60 seconds.

In the measurement of angles, 1/60 of a degree is also known as a minute.

A whole number and a fractional part expressed as a common fraction.

Example: 1 2/3 (one and two thirds) is a mixed fraction. Also known as a mixed number.

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).

For any integers a and b, a is a mulitple of b if a third integer exists such that a = b x c.

Example: 14 = 7 x 2, 49 = 7 x 7 and 70 = 7 x 10. So 14, 49 and 70 are all multiples of 7.

-21 is also a multiple of 7 since -21 = 7(-3).

The operation of combining two numbers to give a third number, the product. Example: 12 x 3 = 36 is a multiplication. Multiplication can be seen as the process of repeated addition.

Example: 3 x 5 = 3 + 3 + 3 + 3 + 3 = 15.

Multiplication is the inverse operation of division, and it follows that 7 ÷ 5 × 5 = 7.