When you're typing in the calculator that comes with iOS 8, and you make a mistake, you probably get frustrated at the lack of a backspace button. However, you can delete individual digits as you type -- the function is just hidden behind a gesture.
This tip comes from Quora user Steve Tamburello: As you type, just swipe to the left or right across the top portion of the app, where the numbers appear. This will delete your most recently typed digit, so if you make a mistake, you can correct it without starting over.
This is an old gesture (it's been around since at least iOS 6), but somehow I never knew about it -- and we've never posted about it -- so hopefully a few of you learned something new!