Robert Swinney wrote:
HP48 is the latest I have, and it's RPN only, but I've got a (n even
older?) clamshell HP financial calculator HP19B that is AE only.

See, HP finally realized that basically non-math types wouldn't want to mess
with all that complexity so they put in AE. But we know the real reason
don't we.

The advantage of using RPN is that you follow the
same sequence of entering numbers as you would do
it by hand. For instance to multiply the numbers
1234 and 5678 with pencil on paper you would first
write down the first number. On the next line
underneath you write the second number. Now you
multiply (or add or subtract whatever) the two numbers.
With RPN you do the same thing: First you key in
the first number. To tell the calculator that the
first number is complete you press enter and then
key in the second number. Next you tell the calculator
what you want to be done: If multiplication then press
the x button, for addition you press the + key etc.
Generally if you know how to solve the problem with
pencil on paper you follow the same sequence on the
RPN calculator.
Persons presented with an lengthy and complicated
equation and not knowing how to go about calculating
the result on paper do prefer the AE calculators.
Somehow they get an answer and belief that it is
correct. However if you know how to calculate that by
hand, then using an RPN calculator comes naturally and
not only that, you 'know' that the calculation is correct.
One guy who had left his RPN calculator at home and
had borrowed an AE calculator said to me: " I repeated
that calculation three times and I am still not confident
that the answer is correct. Can I please borrow your RPN
calculator to get the right answer" HTH
--
SATOR AREPO TENET OPERA ROTAS
Have 5 nice days! John
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