How to delete an app on iphone 4?(read)?

I was organizing my apps out and putting them in folders and when I dragged one app, Quizlet, it disappeared. I went on the app store and typed it in and it's still installed but there's no widget for it. I have to go to the "Search iPhone" thing and type in quizlet to open it. How can I delete it so i can redownload it for the widget?
And yes I have ios7

Ok go to Settings>General>Usage and find the app, press it, than press delete app