If you're holding your iPad with both hands and you know how hard it is to thumb type either in a portrait or landscape view. The good news is that the iOS 5 or 6 gives you an option to split and undock a keyboard.
Touch and hold the "Keyboard" key, choose an option to split or undock a keyboard, and do the same to merge or dock it.
Or use two fingers to unpinch the keyboard to split it, and pinch to merge it.