Maths Terms for 11-13 Yr Olds

In relation to a circle, the distance from the centre to any point on the circle. Similarly, in relation to a sphere, the distance from the centre to any point on the sphere.

In statistics, a selection from a population where each sample of this size has an equal chance of being selected.

A measure of spread in statistics. The difference between the greatest value and the least value in a set of numerical data.

A part to part comparison. The ratio of a to b is usually written a : b.

Example: In a recipe for pastry fat and flour are mixed in the ratio 1 : 2 which means that the fat used has half the mass of the flour. The mixture is 1/3 fat, and 2/3 flour.

A number that is an integer or that can be expressed as a fraction whose numerator and denominator are integers, and whose denominator is not zero. 

Rational numbers, when expressed as decimals, are recurring decimals or finite (terminating) decimals. Numbers that are not rational are irrational. Irrational numbers include square roots and pi, which have infinite, non-recurring decimal places

Data as they are collected, unprocessed.

A number that is rational or irrational. Real numbers are those generally used in mathematics, science and everyday contexts.

The multiplicative inverse of any non-zero number. Example: 1/3 is the reciprocal of 3. Any number multiplied by its reciprocal gives 1. Example 1/3 x 3 = 1. (Division by 0 is not defined and 0 has no reciprocal).

A parallelogram with an interior angle of 90 degrees.

Opposite sides are equal. If adjacent sides are also equal the rectangle is a square. If adjacent sides are not equal, the rectangle is an oblong. Adjective: rectangular.

Bounded by straight lines. A closed rectilinear shape is also a polygon. A rectilinear shape can be divided into rectangles and triangles for the purpose of calculating its area.

A decimal fraction with an infinitely repeating digit or group of digits. Example: The fraction 1/3 is the decimal 0.33333, referred to as nought point three recurring and may be written as 0.3 with a dot over the three. Where a block of numbers is repeated indefinitely, a dot is written over the first and last digit in the block.

In 2D, a transformation of the whole plane involving a mirror line or axis of symmetry in the plane, such that the line segment joining a point to its image is perpendicular to the axis and has its midpoint on the axis. A 2D reflection is specified by its mirror line.

A 2-D shape has reflection symmetry about a line if an identical-looking object in the same position is produced by reflection in that line. Example:

In the shape ABCDEF, the mirror line runs through B and E. The part shape BCDE is a reflection of BAFE. Point A reflects onto C and F onto D. The mirror line is the perpendicular bisector of AC and of FD.

1. Describing a polygon, having all sides equal and all internal angles equal.

2. Describing a tessellation, using only one kind of regular polygon. Examples: squares, equilateral triangles and regular hexagons all produce regular tessellations.

A common property or connection between two or more variables. Example: in a linear graph of the form y = 2x, there is a linear relationship between x and y. For every x, y is half the size. Compare with 'correlation'.

In the context of division requiring a whole number answer (quotient), the amount remaining after the operation. Example: 29 divided by 7 = 4 remainder 1.

A vector that is equivalent to the vector sum of two or more vectors.

A parallelogram with all sides equal.

One quarter of a complete turn. An angle of 90 degrees. An acute angle is less than one right angle. An obtuse angle is greater than one right angle but less than two. A reflex angle is greater than two right angles. Sometimes shortened to 'right' and used as an adjective, e.g. 'in a right cylinder the centre of one circular base lies directly over centre of the other'.

In 2D, a transformation of the whole plane which turns about a fixed point, the centre of rotation. A is specified by a centre and an (anticlockwise) angle.

A 2D shape has rotation symmetry about a point if an identical-looking shape in the same position is produced by a rotation through some angle greater than 0 degrees and less than 360 degrees.