# Number Line – introduction

The number line interaction can be used to create interactive questions for students where points or intervals have to be drawn on a number line.

To create a number line interaction, select Number Line in the list of interactions and click Select.

The Number Line interaction consists of three main fields:

• Solution Editor
• Details editor
• Settings editor

Note

In comparison with the Geometry interaction, this interaction has no Evaluation Criteria. These are indirectly created by the elements defined in the Solution mode in the Details editor, combined with the Tolerance settings.

Solution Editor

The Solution Editor contains all available options for creating, moving and deleting elements from the Number Line interaction panel. The editor is used by the author to define elements visible to the student and elements for evaluation.

Details editor

Using the Mode toggle button, you can define whether you want to add Template elements (visible to the student) or Solution elements (used for evaluation).

The elements created in the Solution Editor, are listed in the Details editor. In case there are elements available in both modes, subgroups are created in the list per mode.

For point elements in the Details editor, additional settings are available when clicking on the element. You can refer to script variables if you want to create a randomized version of the exercise, or you can manually update the position values of the created element.

Settings editor

In the settings editor you can setup the layout of the student interaction for the number line and define the evaluation mechanism.

The following settings are currently available:

General

In the General settings, you can set the tolerance and define whether you want to hide the Toolbar. This last option is particularly useful in case you want to use the number line as a resource/image rather than as an interactive component.

The tolerance defines the error margin a student has for drawing the elements on the number line. The values you can enter are either decimal values (decimal point separated) or integer values.

The values correspond with the scale of the number line. That is, if your number line ranges from 0 to 10, and you set the tolerance to 1, a student is allowed to enter a point between 5 and 7 for the point at coordinate 6.

Boundaries

The Boundaries settings are used to define the lowest and highest value of the number line.

With the following settings:

The number line would look like this (starting at 0, ending at 10):

For more detailed settings on the ticks, refer to the Ticks settings below.

Guide Lines

The Guide Lines setting is available to define the amount of guidelines on which number line elements can be created. You can create multiple guidelines to prevent overlap of intervals. Note that only the horizontal position of an element is taken into account for evaluation. Increasing the number of guide lines is merely a visual enhancement to create a more clear number line.

With an amount of 3 number lines, you can create a setting such as:

Regular Ticks

The Regular Ticks settings control the regular step markings of the number line, commonly named ticks. These are split between major ticks, longer markings that can display their axis value, and minor ticks, shorter markings to indicate smaller increments.

The step size between major ticks is controlled using the Major Step field. The number of minor ticks per major step are indicated with the Minor Divisions input field.

Labels of major ticks can be disabled to only show the step markings. Moreover, the regular ticks can be disabled altogether, resulting in a blank horizontal axis for displaying Custom Ticks (see below) only.

For example:

Will result in a number line with 1 subdivision per major step, and the major steps labelled per integer:

Custom Ticks

Custom Ticks are disabled by default, but can be enabled to define your own marked positions. The Positions list can be extended number-by-number to provide an array of irregular ticks to occupy the number line axis. The values entered should be integer or decimal values, written with a decimal point if applicable.

Note that custom ticks can be used in tandem with regular ticks to highlight specific values.

For example:

Will result in two custom ticks below the number line:

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