You could also type the expression directly into the display without using
the equation writer, as follows:
to obtain the same result.
Change the operating mode to RPN by first pressing the H button.
Select the RPN operating mode by either using the \ key, or pressing
the @CHOOS soft menu key. Press the @@OK#@ soft menu key to complete the
operation. The display, for the RPN mode looks as follows:
Notice that the display shows several levels of output labeled, from bottom
to top, as 1, 2, 3, etc. This is referred to as the stack of the calculator. The
different levels are referred to as the stack levels, i.e., stack level 1, stack
level 2, etc.
What RPN means is that, instead of writing an operation such as 3 + 2 by
we write the operands first, in the proper order, and then the operator, i.e.,
As you enter the operands, they occupy different stack levels. Entering
3` puts the number 3 in stack level 1. Next, entering 2 pushes
the 3 upwards to occupy stack level 2. Finally, by pressing +, we are
telling the calculator to apply the operator, +, to the objects occupying
levels 1 and 2. The result, 5, is then placed in level 1.