Multi-tasking on iPhone or iPad

The multi-tasking option was properly introduced to the iPhone 3GS, iPhone 4 and iPad when IOS 4.2 was released later in 2010. This allows the user to access various apps that are running simultaneously. It comes in very useful when copying and pasting information from one app to another.

How do I access multitasking?
To access multitasking you simply double tap the central button at the bottom of your iPhone or iPad. The screen then appears to slide upward, revealing a selection of apps that are running in the background. Simply tap one of the active apps and the app will suddenly run. If the app is properly set up to work in a multitasking mode, you will not be presented with a splash screen, just whatever the last thing you were doing on the associated app.
How do I disable these apps?
To disable these hold your finger over one of the activated apps for a few seconds, until they start to wobble. When they wobble a minus sign should appear in the corner the app. Tapping on this minus sign does not remove the app from the device, it just turns it off.
Why would I want to disable some of my active apps?
Some apps, when running in the background can drain the power from your device. Further to this, they can also inhibit the function of other apps and slow down the performance of your device.