basicaly its a simple test quiz the slider determines the level of the question which at the moment only level 9 and 10 works with 2 questions each level. When i press the start button its suppose to get a question and a problem depending on the level it should display the first question but all it does is close the app
Your global Current Grade Level is not being set to 9 or 10.
I advise switching from a Slider to a List Picker. You don't need to round their Selection value, you can set their Elements to exactly what you want, and you can use their .Text to show the Selection.