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:
