Maths Terms for 11-13 Yr Olds

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.