The "Perfect" Grade School Calculator?


This has probably been hashed over before, but Wayne Brown's comments re: what to do for the future of RPN dovetailed with some other pondering I've been doing lately.

What would be the features included on the best grade school calculator that H-P (or any company) might produce?

I'll start with the RPN vs. AOS debate & presume it should be an four-level RPN model, with two lines in the display.

More to the point, however, should a student calculator have "square root" and "cube root" and "x^3" etc. keys? It seems to me that limiting early students to x^y, bolstered by the +/- and 1/x keys, should help them understand the ways that exponents work. Don't too many shortcut features mask the underlying functional relationships?

And for logarithms, should they just "go natural" (e^x & LN) or include base-10 log functions as well?

The trig functions are obvious, and the PI constant. Hyperbolics wouldn't make sense for grade school, right?

And all that % and %CHG, etc. is something that should be understood before it's buried under a convenient feature.

With the limitation on programmables in some environments, I wonder whether an SD slot could be incorporated in a very visible spot -- maybe up top, just beneath the display, with the little memory card hanging out a quarter inch or so even when installed. Perhaps the thing wouldn't have program memory unless a memory card was inserted, and hence programmability could be monitored by instructors and test administration types.

Above all, of course, it would have to be inexpensive.

Don't you think that a low cost calculator designed to force a little learning might find a receptive audience in elementary and even high school instructors?


I'm a high school teacher that teach math, physic and chem for 15-16 years old teens. When they bought a normal calculator, they just ask "is there a a/b fraction key and a cube/root key" They also ask if the calculator can do , what they call, "straight entry" like if they want to "solve" ln(2/3*sin(pi/4)+3/2*cos(pi/4)) they really ASK for and NEDD a calculator that they just need to COPY exactly what is ask and get the answer. They also like to view all the entrys they made on the calculator no matter how long it is, so for them, the best calculator to do that is a graphing calculator because the screen is enought large to see long expression. So often graphing calc are too expensive and they buy a casio with two line that is able to scrool all the expression. Thas is what they are looking for!

1) four functions
2) y**x, inverse key,
3) trig
4) LN and LOG
5) square root and cure root and inverse + nRoot key
6) FRACTION keys and fraction simplification
7) 2 lines with scrooling
8) % key (but only 50% know how it works)
9) PI
10) a nice RESET key on the back...

The rest of keys are anoying them!!! Specially the memory keys (they reset the calculator when M, Stat, GRAD is lit in lcd thinking the calculator is bad). FIX, SCI, ENG keys are a big issue too; they don't like when numbers are format and they ask me "what is that number". If it is not written as usual...RESET...

They also dislike the MODE key and all constants, hyperbolic, DMS/DD, logic, etc etc that add nothing but things teachers don't needs in exam...

They don't need manual too; i ask them to read it but it went to the basket with the box when they buy the calculator.

For true, they don't really like TI graphing calculator, they just like the big screen of it. TOO MUCH KEYS AND FUNCTIONS FOR THEM, but it's nice for gaming...

And i'm a teacher that teach to top students in my school, they represent the minority that will study sciences in future higher studies... I use to teach them how to use their calculators but they have many differents models and it's impossible for me to know the procedure on all of them (casio, sharp, TI, and cheaper one). I asked my school to buy about 100 TI-83 plus and all my students now have the same calculator; i try to show them how it works and they ALL told me that they don't whant to know all these functions because they simply don't need them!

At first, i was unhappy about their reaction, but i finally listen to them and saw their view : "a calculator is just a fast TOOL that need only to do what the math teacher ask, if it's mode that the calculator is too complex" and for high school, where the mass of calculators consumer are, their is no need for more in a calculator.

A four function calculator with x**2 and square root is even enought up to 14 years old.

So my conclusion in all is that the HP-33S is possibly target for students but i think that if they buy it it's for the look and not for the functionnality that is too complex for their needs. Possibly, a 20 years old students but not at high school.

Sorry for my faulty english... :-)


Actually, in my experience, I have found quite the opposite.

Most of my friends who are taking physics will use their calculators (generally the TI-89 that you can check out if you are in calculus) for the algebra. Their logic is: "Well I know how to do algebra so I don't have to do it," which I guess is true, but by not doing the algebra, they don't remember it.

I tend to use my calculator's (32sii... I hardly use the 49g+'s solver) solver minimally (I will use it when I want to check if my process is correct to solve an equation and check the answer in the back of the book, but then I go in and work out the algebra)

Now, for algebra 1, geometry, and Algebra 2 students, (and anything below that), I don't think they should need anything but the basic calculator. Most students will use a graphing calculator for these classes, which I believe not only is overkill, but also is hurting their learning. Knowing how to solve an equation and knowing how to solve an equation with your graphing calculator are two totally different skills, the latter requiring much less work.

In theory, what would be nice is a scientific calculator that acts as a CAS (computer algebra system) in simplifying answers. Personally I think that would help students learn the process behind math. Instead of saying ln(3)-ln(5)=-.51082562376, it would say ln(3)-ln(5)=ln(3/5). Also, this ideal calculator would not solve equations or graph.



sounds like an hp 21 to me!


For me it sounds like a 33s with the keyboard layout similar to the 32s (NOT 32sII!) or the 42s. If the calcs would "hide" the most advanced functions in in menus, they maybe would come over them later when they would eventually need them. I love the layout of my 42s because it's very clean and functional.But the student's may think it is rubish because it hasen't got so many functions on the keyboard - so i believe it's a mental problem, too (beside the price).


Ohh HP, won't you give us... a HP43s ;-) (which we would like)


Edited: 28 Feb 2004, 1:55 a.m.


I think a simple calculator should be more than adequate. Most students wouldn't be interested in math and programming like us. Leave the HP33S and the 49 family for those who are interested.

A school calculator should have:
* a working % key: when I add 10% to 100, I should get 110
* trig and inverse trig
* logs and inverse logs (natural only is fine)
* 1/x, x!, square, square root
* fraction conversion is a must
* one variable stats
* RPN/AOS option
* DEG/RAD/GRAD toggle/conversion
* solar panel


* logs and inverse logs (natural only is fine)

and decimal too, for chemistry calculations (pH, pK, etc)


So don't you think that it is normal that calculators manufacturers make calculator less capable than their predessors in order to please their mass consumers that don't want all these functions.

You will probably argue that manufacturers could think about scientist and eng and made them a model with full functionnality even at a greater price? I know a lot of scientist, eng and university teachers that have only a TI-30x of a cheap basic scientific calculator and are completely satisfied with them; they don't need more than my own students in high school too... Some minority eng i know have a HP-20S, a HP-32S and another a TI-83 but they don't use much functions than if they own a HP-35 or a TI-30-LED.

So what consumers a really interest in real programmable calculator with full functions like the HP-42S or 41CX? Perhaps 0,1% of calculator market. So why HP, that has about 5% of that market will make a calculator that fill real needs for a little % of a small 5% market?


I think the percent key should be eliminated. It is the most god-awful stupid excuse for a function anyone ever foisted on a calculator. If you can't turn 27.25% into .2725 in your head, you need more than a calculator for assistance!

Actually, more to the point, is that every calculator I have known, used, or owned, does someting different with the % key---even the HP's are confusing here. There is just no way of knowing what on earth that confounded key will give you for results. GET RID OF IT! i say. and %chg too!

I quickly left it behind with my 11c back in tenth grade---I read the instructions for it and said to myself, "what do I need to remember another useless function for!"

Especially with RPN. Like, you want to find y = x + 20%x? ok, x enter enter .2 * + Or Perccent Change: y enter enter x - SWAP / What do you need that ^#$%#^$# percent key for!


Of course they could be eliminated, but I like %, %T and %CH... (I have even programmed %T in my 15C: sorry, sorry, don't blame me!! ;-)


Hi Raul!

I forgive you---but only if you explain to me what ALG48, Erable, and MetaKernel do and how to install them ;-)

seriously, though, I tried to figure out those three things, and gave up :-{ what to do?

bill [and then an at symbol] plattdesign stop net


MetaKernel is this

Erable and Alg48 are the "parents" of the 49x CAS: programs for symbolic maths

MetaKernel in port1 (128kb RAM card in slot 1)

Erable v3.2 (L788) in port0 (this is described in MK manual: special version for using in port0 with MK in port1)

The other libraries of Erable (Geometry, Prep, Modulo...) and Alg48 (including Intgr) are in port2 (in a RAM card in slot2)

Please read this post

Do you need more info? Feel free for asking
Raul L

Edited: 1 Mar 2004, 6:05 p.m.


The manner in which HPs keep the argument in Y for percent calculations is helpful for me, but I agree it is not intuitive for everyone, and that the "ENTER ENTER 0.2 * +" way is perfectly valid.

What I would condemn is the typical percent key in cheap, four-bangers; its use is a mystery at best. Perhaps it is just kind of a pacifier for the non-math-oriented people, to keep them calm by suggesting that, in the extreme circumstances they may face where a percentage calculation may be needed, there is a key to ease the pain...


Just remember on the older models it saves two program steps when dividing by 100.



I recall a very clever answer by Katie Wasserman to a challenge from (I believe) Valentín Albillo, perhaps a year ago or so. The challege was to divide a number by ten without using numeric input keys. While the intended answer was based in a particular feature of the HP15C, Katie's answer was more general. Assuming the initial value is in X...




will work in any HP. My hat is still off!


I would suggest something like a modern (I mean the technological components, not the looks) incarnation of the HP21.

Then, assuming that simple programming could be an interesting thing to put students (even non-technically oriented ones) in contact with, an HP25 could be the template...

But... also some extra memory, the "sum of y-squared" as part of the "sigma" function, subroutines in place of go-to... all are nice things to have around; so I'm now speaking about the HP29C profile.

And, if battery life is a plus, the HP11C could be the one to try to recreate. (an 11C Platinum? ... but it would be a marketing fratricide against the 33S)

I will stop here, realizing that a 32S, a 32Sii or even a 33s are more contemporary but very valid options. Perhaps a lower version of the 33s (the same product with a less rich function set, but also without the busy and overwhelming keyboard)

Edited: 28 Feb 2004, 7:17 p.m. after one or more responses were posted


A decade ago, Intel was successful selling the 486SX, which was a crippled 486 processor, with the math coprocessor (FPU)disabled. And that situation even allowed for the existence of the 487, sold as an upgrade, which was the same product again, but with a slightly different pin out and with the
FPU enabled this time.

Very clever from a business point of view, they had three products (486DX, 486SX and 487) which were almost the same, and each was profitable in a different market.

HP could offer a 33s "minus", which would be the same 33s that we know today, but with a simpler and less overwhelming keyboard, and enabling just the functions needed at the school market. Some functions could be disabled at power on time (keeping the decimal point pressed at power up seems to be a proven option, as in the Voyagers).

What I don't see as clearly is if they could then charge some money to upgrade the 33s "minus" to a full 33s. Incidentally, the upgrade could be as simple as a cold reset and a keyboard overlay, in 30S fashion...


A XXI-century "blacknut". Or, if the 30s CPU was a "peanut", the 33s can be a "donut", and the option-001 a "chocolate-glazed (hence black) donut"

Edited: 28 Feb 2004, 8:01 p.m.


That was nice:-)


Texas Instruments has spent a lot of money to answer that question. Their core educational calculator product line indicates that there is no single best calculator.


Hi Paul,

One of the options I've thought about is the ability to list the contents of the Y, Z, and T registers in abbreviated form on the top line of the 2 line display. With this option set/toggled you would see the contents of the Y, Z, and T registers in 2 digit scientific notation.

When this option is toggled off, i.e., the normal setting, you would see the contents of the Y register in the current display mode setting on the top line. Needless to say, there are several possible variations. I do believe that the single top line of a 2 line "modern" display would be able to fit 3 numbers in 2 digit exponential notation with small intervening space between them. Might be a problem with 3 digit exponents, however. I would want to avoid the need to do any scrolling of that top line.

Just a thought ...

Edited: 29 Feb 2004, 11:15 p.m.


There have been a lot of interesting ideas presented in this thread, but I have to confess to having something much simpler in mind. I was thinking of an RPN version of those very simple four-function models that you see hanging at the grocery store checkout counter (right next to the keychain flashlights and eyeglass repair kits) or stamped with a company logo and given away as promotional items. My idea was to catch kids who have just finished learning basic arithmetic and are just starting more complicated math, so that the calculator helps speed up things they already can do more slowly by hand but doesn't tempt them to cut corners by having more advanced functions. By the time they start needing log and trig functions they'd be hooked on RPN and would talk Mommy and Daddy into buying a more capable (and expensive) RPN model.


Agreed, just the very basic arithmetic functions for their first calculators. No need for even powers or roots on the calculator until after they've learned about them. Get them accustomed to RPN before they can be indoctrinated into using "algebraic input" calculators and they'll never switch.


Edited: 1 Mar 2004, 11:33 a.m.


By the way, make it cheap enough that if the little darling just happens
to lose or destroy it, it isn't too much of a hardship for the parents.




I would love to have some simple 4 function RPN calculators.

I tend to go camping and backpacking and usually take a calculator with me (the 32sii most of the time, but now the 33s will take its place; less likely to get stolen, or break). It comes in handy for that random math question someone asks, or for more common things such as unit conversion or cooking conversions.

Plus, then I would be able to give one to my 6th grade sister without worrying that I will make her rely on a calculator (I think her TI-36 does too much, although she doesnt know what most of the keys do)

Now RPN started out because it was cheaper to implement than Algebraic calculators, correct (less memory required). (On a side note, I find it ironic that the memory cheap RPN mode scientific calculator now has more memory than anyone could possibly use) It should be much cheaper to produce a pocket RPN calculator, and it would be more powerful than the current grocery store calculators. A 1 line LCD screen, 20 keys, maybe even with a second button to include simple unit conversion, a few bytes of memory, and a small case is all you need.

I wish I had 5 or 10 of these pocket, cheap, RPN calculators, as I am sure we all do for the carry in the pocket at all times. Of course I am also the guy who prefers the 8 cent pens compared to the $1.50.



Edited: 1 Mar 2004, 12:04 p.m.


One aspect of some responses causes me to ask: If one accepts that (in general) there's a problem with math education, does it help to give school kids "what they want"?

Sure, they'll want lots of convenience features. Sure, they'll want to simply copy what has been given them, and then trust (without understanding) that the "right" answer will be spit back at them automatically. Sure, they'll want something on which games may be played.

What if educators were in charge, and were deciding what tool would be used in math classes for the purpose gaining an understanding of math, trig, logarithms & exponents (and maybe statistics)? Does it make sense to have four or six "different" ways to do the same thing? (E.g., e^x, nth root of x, x^2, square root, x^3, cube root.)

(I suppose the fact that I'm not a teacher contributes to my unrealistic approach to this topic!)

Edited: 1 Mar 2004, 2:32 p.m.


I understand that educators did had a role in defining the 48G and 49G family (for instance, forbidding the IR interface for the 49G).

I do prefer the classic RPN models over the RPLs, so I think that the "best" designs had been from old-HP multidisciplinary and "from-different-cultures-and-countries-people" teams.

Nowadays, it seems that very good design ideas come from users (perhaps even from this Forum).

Oh!, certainly not only from students, but appropriate student input should contribute to the whole.


Well, I guess it boils down to the fact that it is cheaper to make 1 calculator model than 2 or 3.

The logic of the company is: Well if someone doesn't want to use the x^3 button, then they won't.

But in reality: If a student has the button, they are going to use it.

It is considerably cheaper to put in more features than the user could possibly use than to make a less powerful calculator, a mid-range calculator, and a very powerful calculator (especially when you only charge 20-50 bucks for it, which is why it is profitable to make different models of graphing calculators)

My freshman year, I had a science teacher (for Integrated Physics and Chemistry) who disallowed any programmable calculator, because about 95% of all programmable calculators used are graphing calculators with so much memory that you can store your life's story in them. Becuase of all the graphing calculators, I could not use my 32sii (even though you can only store about 20 words in the 384 bytes). I was forced to use a TI-30xa (ughh). I probably missed more points from mistyping math problems than from not knowing the material. (Another reason I like the idea of a non-programmable, cheap RPN calculator)

The same teacher now allows programmable calculators (another teacher taught her how to clear all memory on the TI-83+). It turns out she didnt believe one of her students when he told her that the 32sii was programmable (most people believe programmable is the same thing as graphing), so I probably could have used it anyway.

-Ben Salinas



Thank you for your comments.

I would like to suggest you to read my previous posting ( ) and the ones that follow it, about how it may be possible to make just one product, but sell it to different markets with a different function set, without really changing it.

Just a power-on flag or password (like a radix mark selection) will enable partial or full function; most users can be unaware of this.

The "other half" of the solution is to manufacture it as a "blacknut" and give the user a couple of plastic overlays (in 30S fashion) adapted for each function set.

The idea of the password is not to be a secret, but to avoid accidental change of mode.


For your information there is such a calculator already, the Sharp EL9900.

It is Sharp's latest graphical calculator, let's say "middle range" due to some (hard to understand, coming from this respected maker) limitations.

In short the machine has a reversible keyboard, one side being for college students and the other for higher levels.

The concept seems flawed to me, as I don't see the point for the user to voluntarily make many functions unavailable. Maybe if the price of the two versions were different (and the keyboard not being swappable), this would make sense.

So another strange idea whose time has not come in the case of the 9900.


While I would't disable any functions for my own use, I played with the idea of creating a 33s "minus" without developing another product.

The "minus" (I gave the example of the 486SX processor) would have a simpler keyboard (less legends), a simpler manual, less need for support, less phone calls from picky users (like ourselves) and all that simpler options may allow to offer it for a lower price in another market.

Then, an "upgrade" consisting in a plastic overlay may be sold (or given for free, or whatever), and a certain unusual key sequence would enable (or disable again) the more sophisticated functions.

Just ideas...


Semi-relevant to where this topic has gone:

I heard on NPR that there are now some electronic "action figure" toys that contain several extra features which are disabled at the time of purchase, but each of which may be unlocked by watching a designated episode of the cartoon show tie-in.

So (IIRC), Batman "learns" a new phrase every Saturday morning, or something like that. I guess it's implemented via the TV flashing a coded signal that the toy picks up if it's "on" and pointed in the right direction.

I can see it now: "Watch HP-TV at 5:00 for your upgraded SOLVE algorithm!"

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