Maths Terms for 11-13 Yr Olds

In geometry, two lines that are always equidistant (the same distance apart). Parallel lines, curves and planes never meet.

A quadrilateral whose opposite sides are parallel and consequently equal in length.

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

A polygon with five sides and five interior angles. Adjective: pentagonal, having the form of a pentagon.

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%.

Noun: a line or plane that is at right angles (90 degrees) to another line or plane. Adjective: having this property.

The length of any circle divided by the length of its diameter is a constant called pi, which has the symbol below.

Pi is an irrational number. It has an infinite number of non-repeating decimal places. To 8 decimal places, pi is 3.14159265.

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.

An imperial measure of volume applied to liquids or capacity. In the imperial system, 8 pints is equal to 4 quarts, or 1 gallon. 1 pint is just over 0.5 litres in metric (568ml).

The value of a digit that relates to its position or place in a number. Example: in 1482 the digits represent 1 thousand, 4 hundreds, 8 tens and 2 units respectively; in 12.34 the digits represent 1 ten, 2 units, 3 tenths and 4 hundredths respectively.

In geometry, a two-dimensional diagram of a three-dimensional object, usually the view from directly above.

A flat surface. A line segment joining any two points in the surface will also lie in the surface.

The process of marking points. Points are usually defined by co-ordinates and plotted with reference to a given coordinate system. Noun - a collection of these points on a graph.

An element, in geometry, that has position but no magnitude, for example a corner (vertex).

A closed plane figure bounded by straight lines. The name derives from 'many angles'.

If all interior angles are less than 180 degrees the polygon is convex. If any interior angle is greater than 180 degrees, the polygon is concave.

If the sides are all of equal length and the angles are all of equal size, then the polygon is regular; otherwise it is irregular. Adjective: polygonal.

A 3D closed solid figure bounded by surfaces (faces) that are polygonal. Its faces meet in line segments called its edges. Its edges meet at points called vertices. For a polyhedron to be convex, it must lie completely to one side of a plane containing any face. If it is not convex it is concave. A regular polyhedron has identical regular polygons forming its faces and equal angles formed by its surfaces and edges. Example: a cube. Plural: polyhedra.

Any number greater than zero. Where a point on a line is labelled 0 and equally spaced points to one side of it are labelled +1, +2, +3 etc., these, and the numbers represented by decimal points between them, are positive numbers and are read ’positive one, positive two, positive three’ etc.

Symbol: lb. An imperial unit of mass. In the imperial system, 14 lb = 1 stone. 1 lb is approximately 455 grams. 1 kilogram is approximately 2.2 lb.

The factors of a number that are prime. Example: 2 and 3 are the prime factors of 12 (12 = 2 x 2 x 3). See also 'factor'.

The process of expressing a number as the product of factors that are prime numbers.

A whole number greater than 1 that has exactly two factors, itself and 1.

Examples: 2 (factors 2, 1), 3 (factors 3, 1). 51 for example is not prime (factors 51, 17, 3, 1). All prime numbers (except 2) are odd.

A 3D solid bounded by two congruent polygons that are parallel (the bases) and lateral faces formed by joining the corresponding vertices of the polygons. Prisms are named according to the base e.g. triangular prism, quadrangular prism, pentagonal prism etc. Example: If the lateral faces are rectangular and perpendicular to the bases, the prism is a right prism.

The likelihood of an event happening. Probability is often expressed on a scale from 0 to 1. Where an event cannot happen, its probability is 0 and where it is certain its probability is 1. It can also be expressed as a fraction or a percentage. The probability of scoring 1 with a fair dice is 1/6. The chance of rolling an even number is 3/6, or 50%. The denominator of the fraction expresses the total number of equally likely outcomes. The numerator expresses the number of outcomes that represent a 'successful' occurrence. Where events are mutually exclusive and exhaustive the total of their probabilities is 1.

The result of multiplying one number by another. Example: The product of 2 and 3 is 6 since 2 x 3 = 6.

A mapping of points on a three dimensional geometric figure onto a plane according to a rule. Example: A map of the world is a projection of some type such as Mercator's projection. Plans and elevations are vertical and horizontal mappings.

A chain of reasoning that establishes the truth of a proposition.

A proper fraction has a numerator that is less than its denominator.

Example: 2/5 is a proper fraction whereas 9/4 is improper.

Any attribute or characteristic. Examples: One property of a square is that all its sides are equal. A property of rational numbers is that they can be expressed as fractions.

1. A part to whole comparison. Example: Where £20 is shared between two people in the ratio 3:5, the first receives £7.50 which is 3/8 of the whole £20. This is his proportion of the whole.

2. If two variables x and y are related by an equation of the form y = kx, then y is directly proportional to x; it may also be said that y varies directly as x. When y is plotted against x this produces a straight line graph through the origin. If two variables x and y are related by an equation of the form y = then y is inversely proportional to x; it may be said that y varies inversely as x.

An instrument for measuring angles.

A solid with a polygon as the base and one other vertex, the apex, in another plane. Each vertex of the base is joined to the apex by an edge. Other faces are triangles that meet at the apex. Pyramids are named according to the base: a triangular pyramid (which is also called a tetrahedron, having four faces), a square pyramid, a pentagonal pyramid etc.

In a right-angled triangle, the square of the length of the hypotenuse is equal to the sum of the squares of the lengths of the other sides i.e. the sides that bound the right angle.