# Student variable: example

As an example, we will create the exercise:

Find the formula of the straight line through the points $(0,4)$ and $(2,8)$.

• Create a new exercise and enter $y=a x+b$ as task for the solution step.
• Create a new step with the following settings
• name ‘a’
• description ‘the slope’
• task simplify $(8-4)/2$
• Create another step with settings:
• name is ‘b’
• description ‘the offset’
• task simplify $4$

The resulting interaction behaves as follows:

Note the following:

• variables $a$ and $b$ do not occur in the worked out solution
• the student input $y = a x+b$ is not accepted

Let’s now make variables $a$ and $b$ so-called student variables.

Check the box student variable for both steps in the step menu (by clicking the triangle next to the step name).

Run the exercise again and see how variable $a$ and $b$ show up in the worked-out solution and how they can be used by the student.

Note that a student is now able to use the step names as variables, both in the student input for the steps as well as for the definition of the solution step.