In the ancient days, People did manual calculation. Later it was replaced with the calculators. In this modern era, All of them do have mobile phones to do math stuff. iPhone is not an exceptional and it does have normal and scientific calculator app. When the iPhone is held in landscape mode, The scientific calculator can be used. Lots of people do love to work with the touch screens whereas some of them are not and feel little discomfort. Some people will accidentally tap on the beside buttons.
The misspelt characters can easily be deleted by tapping on the backspace button. But when it happens on the calculator app, people do search for the backspace button to swipe them off the screen. It cannot be found, make them feel to scratch their head to search for such one and will worry a little about apple. The apple is really smart and find a way to do things in the same way. Here is a way to do delete the accidentally entered numbers.
Open the calculator app
Enter the numbers
Swipe left or right to delete the numbers in the entered order
Tilt or hold the iPhone in landscape mode to view the scientific mode of the calculator. This will not work in iPhone, If the rotation mode is locked. Unlock it check this out
Tap and hold on the numbers to copy, paste or speak in the desired available language