From GeoGebra Manual
There are two ways of manipulating a free object’s value:
- Change the value of the object by entering its name and the new value in the Input Bar.
- Example: If you want to change the value of an existing number a = 3, type
a = 5in the Input Bar and press Enter.
- Edit the algebraic representation: Activate Move Tool and double click on the object in the Algebra View. This opens a text box where you can edit the object’s value. Press Enter to apply your changes.
Note: While free objects’ values can be changed directly, the values of dependent objects can only be influenced by changing their parent objects or by redefining the dependent object.