OT--Teaching RPN



#51

Hi all.

Similar to the analogy that Macintosh is used in most school systems while the students' homes have Windows PCs, is there a benefit to teaching RPN and how to use an HP calculator at home in lieu of schools & textbooks incorporating TIs into the curriculum?

Edited: 12 May 2012, 10:50 p.m.


#52

Most young students don't see the value of RPN. My son liked RPN a few years ago until his hands touched the TI-89 calculator.

I also don't see many teachers being RPN fans either.

Sooooo .... teaching RPN is not high on anyone in the education business.

Namir

Edited: 13 May 2012, 3:27 a.m.

#53

Hello Matt,

Maybe your question needs a country specific answer. For instance Germany:

It is ruled by brackets "()". Nobody (but for some freaks, most of them students/engineers and even some teachers) use a RPN calc. So the multiplier for the RPN knowledge are schools.

If no one in a school as a teacher makes propaganda for this the pupils have no idea of an alternative.

A second reason is the "high" price for a RPN calc. Because a lot of people (and therefore pupils, too) in Germany don't like math, but they need a calc, so they only want to spent less money as possible (even with bad quality, they think "I only need it for school some years"). They never heard about the benefit of a good calc keyboard.

This is a lost generation, and that will be in future, too.

Sincerely
peacecalc


Edited: 13 May 2012, 5:14 a.m.


#54

Common math employs parentheses - everywhere, not only in Germany. So it's nothing more than sheer consequence that 'algebraic' calcs rule in school where this is taught. At the time pupils are old enough to learn mathematics and know enough to assess tools themselves (which is many years later), other methods have a chance, e.g. RPN. Although I prefer RPN for myself - I learned it at the age of 20 - I won't vote for confusing children with RPN in opposition to the teacher and the whole class. May work in special cases with very math-gifted kids, but not in the average.

Just my 20m€ after having taught mathematics to my own children - mainly without a calculator at all.


#55

Common math doesn't always use parentheses. It uses the vertical position also. A horizontal bar separating numerator and denominator implies that both should be evaluated before the division. The same is true with a raised exponent. People using algebraic calculators need to learn to insert these parentheses.

I think one advantage of RPN is that it forces you to think about precedence of the operations which helps you get it right. This is especially true with things like a^b^c which we discussed here a while back. Most algebraic calculator users would just type the expression withing batting an eye. RPN users would think "wait, is that a^(b^c) or (a^b)^c?" Asking the question will lead to the right answer and a better understanding of the math.


#56

The so called "Math Input" or the equation writers of various kinds solve the problem of the additional parentheses. A similar approach was introduced by the TI-88 with its up and down arrows to start and end an exponential expression. Compared to linear entry, the equation software is often just too slow or too stubborn to be useful.

#57

Quote:
Most algebraic calculator users would just type the expression withing batting an eye.

Right, and if the algebraic calculator is a good one it has the adequate rule build in and it solves a^b^c just correctly. 'Good' in this case meaning using mathematic rules of precedence and not some obscure programming language's parsing. ;-)

#58

Usually it is a school-wide decision to use a certain model of calculator, just to avoid unfair advantages (child A cannot afford super-duper-solve-everything-in-one-keystroke-calculator), this makes teaching much easier too.

Back then, we had much more freedom, and teacher rarely knew anything about calculators, even less about programmable calculators :)

#59

First of all, Macintosh's are not used in most school systems. I don't think I've ever seen a Mac in the public schools here in Kentucky (although some teachers use them). Where schools have computer labs, the computers are always PC clones.

I'd be willing to bet that I'm the only school teacher in Kentucky who knows RPN, and teachers can't teach that which they don't know (not to say it hasn't happened before, however).

Kids don't need to know RPN. That would not help them in their understanding of math. They need to know the basics, and many have not learned the basics yet. The biggest problem in the public schools is that teachers have to teach the official state-approved curriculum, and the math curriculum includes some stupid things that kids will never see or use once they leave school, like stem-and-leaf plots or box-and-whisker plots. Since I teach at a private school, I have the luxury of not teaching that crap, and I don't.

RPN is fun for us old guys to play with, but it has no place in the classroom.


#60

Quote:
teachers can't teach that which they don't know

Is this possible? This is an interesting question I asked myself on a completely different topic: I was able to teach my kids to ride a unicycle without myself being able to only mount one, let alone ride one. ;-)


#61

Quote:
teachers can't teach that which they don't know
I do not speak a word of the Korean idiom. Can anyone tell me how to teach it? Try to teach someone how to fly a pane without even get inside one. In my understanding, actual teachers would never do that.

Quote:
I was able to teach my kids to ride a unicycle without myself being able to only mount one, let alone ride one. ;-)
Are you sure about it? I think that acquiring the ability of riding a unicycle may also come from a personal challenge and some people would learn themselves how to ride one just by trial and error. The unicycle itself must exist and I am almost sure you explained your students what they should do instead of showing them in a practical way. Chances are you have shown someone riding a unicycle, either for real or by audio-visual resources. I also guess you have seen many people riding one of these and got to your own conclusions of what to do to ride one, how to balance, ways of safe falling and you have surely felt yourself safe by studying ways to teach your students about it.

Am I right?

SO... you learned a lot before going ahead teaching. Think of it.

Yep, I'm an engineer and I've been teaching for more than 20 years (with post-graduation in pedagogy). I for one cannot think of a way to teach something I do not know.

Cheers.

Edited: 13 May 2012, 10:08 a.m.


#62

Quote:
I for one cannot think of a way to teach something I do not know.

You can teach a gifted child how to play master-class chess without you being able to play at that level.

Same goes for many other activities, including tennins, martial arts, whatever. You can teach the gifted child or youngster how to excel at it while being unable to do so yourself.

Regards.
V.


#63

Hi, Valentin.

I agree with you. Anyway, the kid must be gifted, otherwise he will mostly get only the basic rules. And you must know the basics prior to teach.

You can teach someone how to climb an escalator to the top by showing just the first step, you do not need to climb it to the top yourself. But you must, at least, know yourself how to perform the first step (or have the means to show it) and the learner should understand it.

Cheers.

Luiz (Brazil)

Edited: 13 May 2012, 12:06 p.m.

#64

Of course you're right. I wanted to point out that there is a difference between 'knowing about a topic' and 'knowing to do it yourself'. One can teach numerous things without being able to perform them. How else could a world class tenor have a singing teacher?
I guess it's the essence of teaching that the pupil always can out-perform the teacher. Lucky the teacher who can witness and enjoy that.


#65

Agreed!


#66

There is an expression mostly used in the trades where some physical ability comes into play. "Those who can't do,teach." I think good teachers are as necessary as good doers.


#67

Hi, Ethan.

Quote:
"Those who can't do, teach."
I always had this expression into some foggy perspective, mostly because there are others with the same structure and different meanings, like "Those who can't think, fight!". But having the difference between 'can' and 'may', the expression has a valid basis.

You see, in Portuguese both meanings - may and can - are expressed by one verb alone, so if one says 'Não posso' (Portuguese), we never know if it is 'I can't' - not capable of - or 'I may not' - not allowed to, or not supposed to -. Same for 'Can I?' and 'May I?', both expressed by 'Posso?' indistinctly.

Are we still in the subject? I have the feeling I have drifted it beyond repair.

Cheers.

Luiz (Brazil)

#68

Hi, Don.

Quote:
RPN is fun for us old guys to play with, but it has no place in the classroom.
I guess George Boole had heard a lot of that about his boolean logic... It took decades for its ingenious logic proposal to take place. World was not yet ready for that...

Cheers.

Luiz (Brazil)


Edited: 13 May 2012, 10:30 a.m.

#69

Don, I am a teacher in Kentucky who knows (and loves) RPN. Where abouts are you located?

#70

At the college where I teach, the "official" recommended calculators are TI graphing models and the courses contain tutorials for using those but, subversive that I am, I never make much of that and try to make at least a mention of RPN alternatives.

#71

Quote:
Hi all.

Similar to the analogy that Macintosh is used in most school systems while the students' homes have Windows PCs, is there a benefit to teaching RPN and how to use an HP calculator at home in lieu of schools & textbooks incorporating TIs into the curriculum?



I think so Matt, RPN "forces" the user to think about the order of operations. RPN allows the user to see immediate results and save a few keystrokes.

HP should release a basic RPN solar powered calculator, even a simple scientic (original HP 35) or just a basic one.


#72

Quote:
HP should release a basic RPN solar powered calculator, even a simple scientic (original HP 35) or just a basic one.

I second that!

#73

So do I!

#74

Quote:
RPN allows the user to see immediate results and save a few keystrokes.

Isaac Asimov, in his short story The Feeling of Power, envisioned an RPN future:

"I'm almost done, sir. Here it is, sir. Forty-one million, five hundred and thirty-seven thousand, three hundred and eighty-two." He showed the scrawled figures of the result.

General Weider smiled bitterly. [Having previoulsy entered the numbers 5,738 and 7,239] he pushed the multiplication contact on his computer and let the numbers whirl to a halt. And then he stared and said in a surprised squeak, "Great Galaxy, the fella's right."

Isn't this RPN or what? :-)


#75

Hi, country mate.

Thank you for the outstanding example.

So, in the future, people will understand RPN and its importance... Great zciweisakuL!

Edited: 13 May 2012, 2:07 p.m.


#76

Olá, Luiz!

Quote:
So, in the future, people will understand RPN and its importance... Great zciweisakuL!

I have to tell you the general was amazed because the guy was able to perform that multiplication using only paper and pencil, which everyone had long forgotten. But I don't want to spoil the story anymore :-)

Cheers,

Gerson.


#77

Yep, I got it. I had in mind that the very simplest example used in the first steps into RPN, seen in all good, old-timer HP manuals, is the one showing how close it is to a pencil 'n paper calculation. I myself do the same when explaining RPN to a beginner.

Cheers.

Edited: 13 May 2012, 2:47 p.m.


#78

See page 15, por favor :-)

#79

Quote:
I had in mind that the very simplest example used in the first steps into RPN, seen in all good, old-timer HP manuals, is the one showing how close it is to a pencil 'n paper calculation. I myself do the same when explaining RPN to a beginner.

Showing how close RPN is to pencil and paper calculations nearly always uses addition as the example. It never uses division as the example. Why do you suppose that is?

#80

My hunches are that division is more often written horizontally (e.g.

_____

3)27

(Sorry, I can't get the division to look right. But, I think you know what I mean.)

You have a point. even division written as a vertical fraction makes sense in the stack metaphor. But, I think that because divisions are most often written horizontally or like the form I cited above, the stack analogy is missed.


Edited: 13 May 2012, 10:43 p.m.

#81

Hi.

I guess that one may write the arithmetic operations themselves in many ways. I mean:

2  3  +  (kinda FORTH like)

7 ÷ 8

3
× 5

Either the algebraic or the reverse Polish are, after all, notations. Piling the numbers when adding, multiplying or subtracting makes it easier to actually perform the operations with paper and pencil. Because division itself is not actually performed when using paper and pencil, instead it is a sequence of multiplications and subtractions, aligning divider and divisor side by side allows numbers to be pilled under the divider so they can be sequentially subtracted.

I am not sure I used the correct English terms to express myself. 8^(

Cheers.

Luiz (Brazil)

(added after editing) I remembered now that notation for division in Brazil follows a different arrangement of the one in the USA.

Edited: 14 May 2012, 2:24 a.m.


#82

Quote:
I remembered now that notation for division in Brazil follows a different arrangement of the one in the USA.



The notation varies quite a bit worldwide: long division


#83

Thanks. Very good article, indeed.

I ended up trading 'dividend' (closer to Portuguese) for 'divider' (closer to my inability of accepting that I do not know everything by heart.. Poor me). In all cases, the multiplication-and-subtraction sequence is followed, and the reminders are pilled under the dividend.

These methods are notation independent, though...

Cheers.

Luiz (Brazil)

Edited: 14 May 2012, 5:36 a.m.

#84

My vote would be a solar powered model which is a higher quality version of the 30S (RPN, of course).

Edited: 14 May 2012, 4:09 p.m.

#85

Within 2 years, we aren't going to see calculators of any sort in schools. Book neither. Its all going to tablets.

Ironically, on the eve of the "paperless" school, children's textbooks have gotten heavier on average than ever before in history--full of glossy cutesey photographs--in exactly the correct racial distribution--of students holding erlimeyer flasks, wearing googles, holding metric scale rules, while smiling and studiously taking notes, rather than a actual "content".

Calculators will be replaced by touchscreen "apps" rather than machines...


#86

I wonder, though, how examinations requiring calculations will be administered: what besides a plain-vanilla handheld calculator might be allowed?

Other than that, it seems clear that the hhc can be dispensed with, except by fans.

#87

I gotta say though, in light of what I saw today (an elderly lady playing Scrabble(R) on an iPad), with the tablet's degree of user-intuitiveness, it may be that if the techno marvels presently available are this easy to use by an older generation and those who are not so tech savvy, the tablet may be the future of handheld computing for practically all folks from luddite to those with Masters in CS.


#88

I call iPads and eBooks 'electronic cretinizers', and hold Gates, Jobs and the like to be responsible for the decline of the printed book. The positive side is that the energy from a future Coronal Mass Ejection could wipe out all the downloaded trash fiction at once.


#89

:-)

#90

Your calculator(s) would survive the CME? Be careful what you wish for. Lol


#91

My mechanical ones would still work, but I'd probably need a good supply of candles or whale oil for night calculations.

#92

I'm gonna side with you on this one. Since I grew up during the dawn of the TI 2500 era and had my first programmable, an SR-56 right from Freeway Stores, I have been and ALWAYS WILL BE partial to the bona-fide handheld calculator. Even my conversion to HP by way of studying HP manuals and getting my first two HPs, a 32E and a few months later, a 34C as a fulfilled birthday wish firmly implanted HP loyalty and RPN as my mathematics mission statement. So yes, it saddens and frustrates me to see iPads, Nooks, Kindles, and (dare I say) Wintel Tablets relegating the physical calculator to the rest home and probably later to the eWaste cemetery. But, not even this pressing your fingers onto a flat tablet surface with its mimicky feel of keypresses can match the sheer experience of thumbing through and running your finger across a spiral-bound HP-67, HP34C manual and the double-shot tactile feel of calculating and solving roots of equations, integrals, matrices or just to explore your basic log & trig identities.

But, thanks to all you here and others who take on the loving tasks of restoring not only legendary calculators but even their exclusive and archaic technologies like LED displays, card readers and tape drives. Because of this community of calculator owners, collectors and aficionados, the handheld calculator can remain an immortal member of the technical and mathematical world.

Edited: 15 May 2012, 11:01 p.m.


#93

To me the ultimate handheld calculator will always be the Curta. I have fond memories of watching our instrument man's antics out in the woods as he calculated coordinates surrounded by mosquitos. Cranking the Curta, looking up functions in his book of tables, writing down numbers, swatting, scratching himself and cursing would be a great exercise in multi-tasking. Now and then he'd snap the book shut in order to exterminate individual mosquitos, which was effective but resulting in squashed remains scattered amongst the sines and cosines.


#94

Wow - now THAT's gotta be the best user case posting in a while! Thank you for that!

Jim (happily in the US NorthWest, unlike where I grew up with giant mosquitoes...)


#95

Quote:
... where I grew up with giant mosquitoes...

Didn't know yet these airborn animals have toes ;-)

#96

Fortunately with modern calculators such as the HP 35S the bugs are on the inside.


#97

D'oh! :-)

#98

My "working with bugs" story is from the flight test of the Fairchild SD-5 drone at the Yuma Test Station. The rainy season was followed what the locals called "cricket season" although I think the crickets were really some kind of locust. They could not only crawl and jump but could also fly. Synching a Tektronix scope with one crawling up your leg and another down the back of your neck was an exercise in concentration. When the crickets got really bad there were individuals patrolling the perimeter of the hangar and picking up the incoming crickets in vacuum cleaners. When the vacuum bags were filled they were taken out in the desert and burned. Cricket season was followed by beetle season. The beetles were big ugly black animals but thankfully they were slow moving.


#99

At one time I had hopes of cross-breeding chickens with centipedes and thereby achieving a 50:1 ratio of drumsticks to wings. The plan was to make a lot of money supplying the fast food franchises, but every breeding attempt ended in failure as the chickens invariably ate the centipedes.
The next venture was to cross a yew tree with a geranium in order to produce a fissionable plant that could sold to nuclear power staions. That also ended in failure...

As a proud owner of one myself, I too can appreciate all of its character and functionality. And yes, as I give my friends & relatives a tutorial, they are very intrigued and fascinated.


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