Finished App

main.py

 from kivy.app import App
 from kivy.modules import inspector # For inspection.
 from kivy.core.window import Window # For inspection.
-
+from kivy.properties import NumericProperty
 __app_package__ = 'edu.unl.cse.soft161.order'
 __app__ = 'Order Meal'
 __version__ = '0.1'
@@ -12,7 +12,30 @@ class OrderApp(App):
     def build(self):
         inspector.create_inspector(Window, self) # For inspection (press control-e to toggle).
 
+    total = NumericProperty(0)
+    def addDoubleDoubleToOrder(self):
+        if self.root.ids.doubleDouble.active:
+            self.total += 6.50
+            print(self.total)
+        if not self.root.ids.doubleDouble.active:
+            self.total -= 6.50
+            print(self.total)
+
+    def addCheeseburgerToOrder(self):
+        if self.root.ids.cheeseburger.active:
+            self.total += 5
+            print(self.total)
+        if not self.root.ids.cheeseburger.active:
+            self.total -= 5
+            print(self.total)
 
+    def addHamburgerToOrder(self):
+        if self.root.ids.hamburger.active:
+            self.total += 5
+            print(self.total)
+        if not self.root.ids.hamburger.active:
+            self.total -= 5
+            print(self.total)
 if __name__ == '__main__':
     app = OrderApp()
     app.run()

order.kv

 BoxLayout:
     orientation: 'vertical'
-    Label:
-        text: '[Your meal-ordering GUI here]'
+    BoxLayout:
+        orientation: 'horizontal'
+        Label:
+            text: 'In-N -Out Burger'
+            font_size: 30
+            color: (0.8,0,0,1)
+    BoxLayout:
+        orientation: 'horizontal'
+        CheckBox:
+            id: doubleDouble
+            on_active: app.addDoubleDoubleToOrder()
+        Label:
+            text:'Double-Double'
+            font_size: 24
+            color: (0.8,0,0,1)
+    BoxLayout:
+        orientation:'horizontal'
+        CheckBox:
+            id: hamburger
+            on_active: app.addHamburgerToOrder()
+        Label:
+            text:'Hamburger'
+            font_size: 24
+            color: (0.8,0,0,1)
+    BoxLayout:
+        orientation: 'horizontal'
+        CheckBox:
+            id: cheeseburger
+            on_active: app.addCheeseburgerToOrder()
+        Label:
+            text:'Cheeseburger'
+            font_size: 24
+            color: (0.8,0,0,1)
+
+    BoxLayout:
+        orientation: 'horizontal'
+        Label:
+            text:'Total: $' + str(app.total)
+            font_size: 24
+            color: (0.8,0,0,1)