With over 9 million iPhones sold in just three days, and undoubtedly millions more since Apple first announced the impressive sales figure, there are likely many people experiencing iOS for the first time.

That being the case, here's a quick Calculator app tip that maybe even seasoned iOS users will find new and useful.

It's not readily apparent, but the Calculator app in iOS has a hidden gesture that enables you to delete numbers from an entry if you happen to input a number by accident.

As a quick example, let's say I'm trying to input the number 5,964 but accidentally type in 596,487.

Is all hope lost? Do I have to start over from scratch?

Not at all!

To erase a number, digit by digit, simply swipe to the right on the number display and the most recently entered digit will disappear. This handy trick is a lifesaver if you happen to be a few calculations deep and don't want to start over from scratch.

So in the example above, I just need to swipe to the right twice and I'm well on my way toward calculator bliss.