User Story: I can keep chaining mathematical operations together until I hit the equal button, and the calculator will tell me the correct output. Remember to use Read-Search-Ask if you get stuck.

If the clicked button has the inner HTML content "DEL" (delete), the calculator removes the last character from the current expression and updates the input field. For all other buttons (numeric ...

The current iPhone calculator doesn't have a backspace button – but you can swipe left on digits to delete them Credit: Apple. One added: "OK so apparently we have been able to swipe for ...