HP 33s hp 33s_user's manual_English_E_HDPM20PIE56.pdf - Page 105

„ To change the number, type the new number and press g. This new number writes over the old value in the X-register. You can enter a number as a fraction if you want. If you need to calculate a number, use normal keyboard calculations, then press g. For example, you can press 2 ‘ 5 g. „ To calculate with the displayed number, press ‘ before typing another number. „ To cancel the prompt, press ‡. The current value for the variable remains in the X-register. If you press ‡ during digit entry, it clears the number to zero. Press ‡ again to cancel the prompt. „ To display digits hidden by the prompt, press | . Each prompt puts the variable value in the X-register and disables stack lift. If you type a number at the prompt, it replaces the value in the X-register. When you press g, stack lift is enabled, so the value is retained on the stack. The Syntax of Equations Equations follow certain conventions that determine how they're evaluated: „ How operators interact. „ What functions are valid in equations. „ How equations are checked for syntax errors. Operator Precedence Operators in an equation are processed in a certain order that makes the evaluation logical and predictable: Entering and Evaluating Equations 6-13