How to kill or force quit apps on iOS 9
Some apps—especially the Facebook, Skypes, and big media apps of the world—don't always behave well on iPhone, iPod touch, or iPad. When and if that happens, you can try "force quitting" them. iOS 9 almost always handles pausing and shutting down apps just fine. So, force quitting isn't something you should do often, because re-launching it again from scratch will consume more power and take more time as it updates in the foreground, but it is something you should know how to do for when you need it.
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