Closing apps in iOS 6 was different that what is now in iOS 7. Shown in the video below is the old clumsy way of closing apps on the old iPads.
Closing the apps prevents from taking up precious memory, resources and battery charge. Simply quit of the screen with the closing arm doesn't work. The Application is still running.
Two times pressing the home button brings the bar on the bottom of the screen.
If you have many applications, you may need to slide to find the one you want to close.
With holding of the finger, you tell iOS that you want to have closing minuses on the applications icons.
Animation showing that the applications are now ready to be closed.
That's it. With the close of the app it will be removed from the memory in full. No longer slowdown because of too many opened apps. Enjoy you iPad, iPhone or iPad mini. You shall always try to keep your iOS clean, so it doesn't become mess in the future.