Operating Modes; Rpn Mode - HP 35s Quick Start Manual

Operating Modes

The HP 35s has two operating modes: Reverse Polish Notation
(RPN) and Algebraic mode (ALG). RPN is usually more efficient
than Algebraic, requiring fewer key presses to solve most prob-
lems. It is also particularly helpful when working through a prob-
lem one step at a time, as all intermediate answers are
displayed.
Algebraic mode allows an expression to be keyed in the order it
is written. No intermediate answers are displayed, as the final
result is calculated in one step.

RPN Mode

Press 9 to set the calculator to RPN mode. When the
calculator is in RPN mode, the RPN annunciator is on. In RPN
mode, the result of any computation, whether simple or com-
plex, can be used as the input for the next calculation. RPN uses
a 4–level stack to hold intermediate or previous results. In RPN
mode, values are entered first and then an operation is per-
formed.
The X and Y–registers are displayed, unless a menu, a message,
an equation line, or a program line is displayed. The X–register
is the bottom number displayed, and the Y–register is the top
number. Several function names include an x or y. These refer to
the X– and Y–registers. For example, ! raises ten to the
power of the number in the X–register. The other two stack regis-
Getting Started 9