A positive real number is expressed in **scientific notation** when it is written as the product of a power of 10 and a decimal that has just one digit to the left of the decimal point.

For example, the scientific notation for 3459 is and the scientific notation for 0.000004567 is

Many electronic calculators will show these as 3.459E3 and 4.567E-6

**Primary data** is data collected by the user. **Secondary data** is data collected by others. Sources of secondary data include, web-based data sets, the media, books, scientific papers, etc.

A **polygon** is plane figure bounded by line segments.

The figure shown above is a **regular pentagon.** It is a convex five-sided polygon. It is called a **pentagon** because it has five sides. It is called **regular** because all sides have equal length and all interior angles are equal.

A **polyhedron **is a solid figure bounded by plane polygonal faces. Two adjacent faces intersect at an edge and each edge joins two vertices.

The polyhedron shown above is a pyramid with a square base. It has 5 vertices, 8 edges and 5 faces. It is a convex polyhedron.

The figure above is a non-convex polyhedron.

A **convex polyhedron** is a finite region bounded by planes, in the sense that the region lies entirely on one side of the plane.

A regular shape can be a polygon. A polygon is regular if all of its sides are the same length and all of its angles have the same measure.

have the form of a single clause (for example, 'David walked to the shops.' or 'Take a seat.')

meaningful elements added to the ends of words to change their meaning (for example, to show its tense: 'ed' in 'passed'). Common suffixes are 'ing', 'ed', 'ness', 'less' and 'able')