Maths Terms for 11-13 Yr Olds

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.