This iPhone tip makes a huge difference if you use the Calculator app often. Have you ever had this frustrating Calculator experience? You go to the Calculator app on your iPhone and start entering a long number, but you mistype a digit or two. Up until now, you may have thought that you had to hit C for clear and start all over. Am I the only person who wonders why Apple didn't just include a backspace button? However, while there isn't a backspace button visible, there is a hidden iPhone trick that will do the same thing. Here’s how to delete digits in the iPhone Calculator app.