# Undo Operation; The Rpn And Alg Keys - HP 12C Platinum User Manual

Financial calculator.

20
Section 1: Getting Started

## Undo Operation

Every
time
you
fCLEARG key to clear data, the
This means you can press gß to undo the last operation (i.e., to recover the
data.)
Note:
the Undo function is only available immediately after data has been
cleared. When the Undo indicator is turned off no operation can be undone.

### The RPN and ALG Keys

The calculator can be set to perform arithmetic operations in either RPN (Reverse
Polish Notation) or ALG (Algebraic) mode.
In Reverse Polish Notation (RPN) mode, the intermediate results of calculations are
stored automatically, hence you do not have to use parentheses.
In algebraic (ALG) mode, you perform addition, subtraction, multiplication, and
division in the traditional way, using parentheses if needed.
To select RPN mode:
the calculator is in RPN mode, the RPN status indicator is lit.
To select ALG mode:
the calculator is in ALG mode, the ALG status indicator is lit.
Example
Suppose you want to calculate 1 + 2 = 3.
In RPN mode, you enter the first number, press the \ key, enter the second
number, and finally press the arithmetic operator key: +.
In ALG mode, you enter the first number, press +, enter the second number, and
finally press the equals key: }. Don't forget to press OO before doing the
calculation.
RPN mode
1 \ 2 +
You can choose either ALG (Algebraic) or RPN (Reverse Polish
Notation) mode for your calculations. Throughout the manual, most
examples are shown in both modes. The Keystrokes column will
indicate RPN mode or ALG mode where the keystrokes differ. When
the
keystrokes
"Keystrokes".
press
O,
gÚ,
status indicator appears in the display.
Press f] to set the calculator to RPN mode. When
Press f[ to set the calculator to ALG mode. When
are
the
same,
fCLEARH,
fCLEAR²
ALG mode
1 + 2 }
the
column
is
or
simply
titled