HP 35s HP 35s scientific calculator - User Guide - Page 20

Backspacing and Clearing Among the first things you need to know are how to clear an entry, correct a number, and clear the entire display to start over. Key   Keys for Clearing Description Backspace. If an expression is in the process of being entered,  erases the character to the left of the entry cursor ( _ ). Otherwise, with a completed expression or the result of a calculation in line 2,  replaces that result with a zero.  also clears error messages and exits menus.  behaves similarly when the calculator is in program-entry and equation-entry modes, as discussed below: Equation-entry mode: If an equation is in the process of being entered or edited,  erases the character immediately to the left of the insert cursor; otherwise, if the equation has been entered (no insert cursor present),  deletes the entire equation. Program-entry mode: If a program line is in the process of being entered or edited,  erases the character to the left of the insert cursor; otherwise, if the program line has been entered,  deletes the entire line. Clear or Cancel. Clears the displayed number to zero or cancels the current situation (such as a menu, a message, a prompt, a catalog, or Equation-entry or Program-entry mode). 1-4 Getting Started