added a progress bar

main.py

@@ -75,6 +75,7 @@ class QuizzerApp(App):
     paused = BooleanProperty(False)
     correct = BooleanProperty(False)
 
+    questions_answered = NumericProperty(0)
     score = NumericProperty(0)
 
     def build(self):
@@ -113,6 +114,7 @@ class QuizzerApp(App):
         if self.correct:
             self.score += 10
         Clock.schedule_once(lambda delta: self.unpause(), PAUSE_TIME)
+        self.questions_answered += 1
 
     def unpause(self):
         self.paused = False

quizzer.kv

@@ -89,6 +89,9 @@ ScreenManager:
                 text_size: (self.width, None)
                 halign: 'center'
                 color: (0.0, 0.0, 0.75, 1.0) if not app.paused else ((0.0, 1.0, 0.0, 1.0) if app.correct else (0.5, 0.0, 0.0, 1.0))
+            ProgressBar:
+                value: app.questions_answered
+                max: 5
             GridLayout:
                 rows: 2
                 Button: