Maths Terms for 11-13 Yr Olds

The length of any of the chords of a circle or sphere that pass through it's centre. Compare with 'chord'.

The amount by which one number or value is greater than another, obtained by subtracting the smaller from the larger.

1. An operation on numbers interpreted in a number of ways. Division can be sharing - the number to be divided is shared equally into the stated number of parts; or grouping - the number of groups of a given size is found. Division is the inverse operation to multiplication.

2. On a geometric scale, one part. Example: Each division on a ruler might represent a millimetre.

A polyhedron with twelve faces. The faces of a regular dodecahedron are regular pentagons. A dodecahedron has 20 vertices and 30 edges.

1. The vertical height of a point above a base (line or plane).

2. The angle of elevation from one point A to another point B is the angle between the line AB and the horizontal line through A.

A transformation of the plane in which lengths are multiplied whilst directions and angles are preserved. A centre and a positive scale factor are used to specify an enlargement. The scale factor is the ratio of the distance of any transformed point from the centre to its distance from the centre prior to the transformation. Any figure and its image under enlargement are 'similar' - having the same internal angles and ratios between the length of its sides.

An adjective describing a polygon with sides of equal length.

A mathematical form expressed symbolically. Examples: 7 + 3; a² + b².

An expression is different from an equation in that it doesn't have an equals sign =. 

In geometry, one of the flat surfaces of a solid shape. Example: a cube has six faces.

Symbol: ft. An imperial measure of length. 1 foot = 12 inches. 3 feet = 1 yard. 1 foot is approximately 30 cm.

Imperial measurements are rarely used in modern times.