Maths Terms for 11-13 Yr Olds

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'.