I have owned an IPhone for almost 9 years and had no idea. I use my calculator more than any app on my phone (mostly because I am Math-challenged…don’t judge me).
BOOM! You can backspace on your IPhone calculator just by swiping the number you want to get rid of…now you don’t have to clear it out when you screw up with your butterfingers.
That’s always my excuse, at least. Again…don’t judge me.