HP HP-21 - A Word about the

Getting Started 15
Now try these problems. Remember to work through them as
you would with a pencil and paper, but don’t worry about inter-
mediate answers—they’re remembered automatically by the
calculator.
Problems
2x3)+@4x5)=[2600
(14 + 12) x (18 — 12)
S
(\/ 163805><
)= Geioo
[(17 - 12) x 4] = (10 -5 = [400
VR +3)X@+95 + Ve+T7xB+9 = |21.57
A Word about the HP-21
Now that you’ve learned how to use the calculator to solve
complicated problems, you can fully appreciate the benefits of
the Hewlett-Packard logic system. With this system, you enter
numbers using a parenthesis-free unambiguous method called
RPN (Reverse Polish Notation).
It is this unique system that gives you all these calculating
advantages:
m You neverwork with more than two numbers at a time. The
HP-21 cuts problems down to size instead of making them
more complex.
m Pressing a function key immediately executes the function.
You work naturally through complicated problems, with
fewer keystrokes and less time spent.
m Intermediate results appear as they are calculated. There
are no ‘‘hidden’’ calculations, and you can check each
step as you go.
» Intermediate results are automatically stored. You don’t
have to write down long intermediate answers when you
work a problem.