Before beginning this unit we assume that students have already worked with some functions, in particular functions which deal with proportion. Through the activities in this unit we expect the students to build on their existing knowledge to find out more about functions and learn how to interpret graphs of functions.

The activities focus on plotting points from coordinates and reading straight line graphs, i.e. being able to identify different types of graphs depending on their gradient and position on the axes.

• Identify different linear functions by their gradient.

• Draw linear function graphs according to their gradient.

• Identify the main characteristics of linear functions.

• Obtain the equation of a straight line that passes through the origin.