A graphics calculator screen allows for graphical representations of functions to be obtained readily, and easily interrogated. Figure 5 shows an example of two (user-defined) functions in a function list, and their graphical representations (obtained with the press of a key). This important capability resulted in early descriptions of graphics calculators as ‘graphing’ calculators. The graphical representations themselves can be manipulated (for example by tracing, as shown in Figure 5, or by zooming to see different views) and students can move freely between definitions of functions and their graphs. This offers powerful ways for students to learn about the visual appearance of functions, of great importance to learning about their properties and their uses. In this case, the line and parabola are fundamental shapes of great significance to students learning about functions.