Calculator Fix Most People Don't Know About

This isn't in anyway a 'cool' tip or something that will change the way you view the iPhone all together, but it is a little trick that has saved me from a lot of frustration since learning about it. 
For the longest time whenever I made the mistake while I used the calculator, I would just hit the 'C' button and zero the calculator, and start over. But, if you are looking just to remove the last number of what is appearing, all you have to do is to swipe left or to swipe right in the black area surrounding the number. 
It doesn't seem like a lot, but for someone who is constantly using a calculator for the work that I do, it is definitely something that I greatly enjoyed figuring out as it has saved me a lot of time and effort since learning about it.