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Recently I found the site Geek and Poke and their comics are sooo funny! Yesterday the topic was RPN HP calcs:

You see, the answer is not always 42 ;-)

I can also recommend the first Geek&Poke book they provide on the web site. I'm not affiliated in any way with this web site but you know: a laugh a day keeps the doctor away ...

Enjoy,

Juergen

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I don't get it!!!!!

<very wide grin>

Namir

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Let me guess: "this joke is funny because...... he got the wrong answer"?

Jeff Kearns

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Don't see how the answer is wrong.

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Maybe he means because it isn't 42?

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The "old geek" computes mentally in RPN.

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He gets it. He's just an old geek... like me.

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Manuals and books for RPN calculators typically contend that one of the advantages of RPN is that users can solve problems on their calculators in a manner similar to the way they would solve them with pencil and paper. For example,

Page 29 of the *HP-41C Owner's Handbook and Programming Guide* says about RPN that "You can calculate in the same manner you do with pencil and paper. ..."

Page 327 of the *HP 19BII Financial Calculator Owner's Manual* says "You can calculate in the same order as you would with pencil and paper -- that is, from the innermost parentheses outward."

Pages 38 and 39 of the Fifth Edition of Wlodek's *A Guide to HP Handheld Calculators and Computers* say the same thing but in much more detail.

That all may be true, but do RPNers REALLY solve elementary problems such as the one proposed here in their head using RPN as suggested in the cartoon or do they simply do it in algebraic?

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I kind of suspect it would be a hybrid: if I was parsing the problem to understand and envision it, I would probably be thinking in an algebraic sense. If I had to evaluate it with my (RPN!) calc, then RPN it would be.

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If the expression is not trivial and there are parenthesis I start at the inner expression and go on to the outside. The only problem is that my brain has a very limited stack ;-) so I have to write down intermediate results. Anyway, it's the RPN way, and it's the natural way of computing such expressions mentally. My brain calculator does not provide parenthesis.

- Juergen