HP (Hewlett-Packard) HP 33s ユーザーズマニュアル

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Entering and Evaluating Equations 
6–13
„
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: