In iOS 6, it was simple to stop any apps running in the background. All you had to do was double-tap the home button, hold the apps down, and hit the minus sign to stop them from running in the background.
With iOS 7, users can see what is currently happening in the background apps, such as music playing, call waiting, etc., and decide whether to stop the apps from running in the background in order to maximize battery life.
To do this, double-tap the home button and simply flick the apps off the screen with an upward finger motion.
but that's not all. I found myself with dozens of apps running in the background and I felt it was less efficient to delete the apps one by one, so I played around with my iPhone and tried something different.
I figured out that I could stop multiple apps from running in the background simultaneously. With the flick of two or three fingers, the iPhone will stop two or three apps at a time from running in the background.
Try this out when you find yourself wanting to stop multiple apps without taking the time to stop them one-by-one. Sound off in the comments if this trick helps you.