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HOWTO Close apps on iPad/iPhone/iPod Touch
You may find your iPad or iPhone slowing down a bit. This might be because you have a number of apps still open when you thought they were closed. The following instructions may help solve the problem.....
Double click the on/off button
Your screen will change and any apps visible are the 'open' apps.
Hold your finger on any one of the open apps. A red/white symbol will appear. Touch the symbols and the app will close.
This will also work with your phone and iPod touch. This will not delete the app. A black x indicates deletion