Graphing Calculator suggestion


Good morning.

I find out from my son (Dezso), just now, that he will need a graphing calculator for his math class next year. School recommend a TI brand, but I do not like TI. What is good calculator by HP that have good feel and good functions for graphing calculator. Should I be looking for used calculator, or new. I would like to find the best one for him is possible, but I do not want to pay a fortune for it.

Edited: 27 July 2007, 11:08 a.m.


Go with what the school recommends. My 16-year-old uses a TI-83+, as does every student and teacher in her school. It is required. All the homework, tests, lectures, etc... assume a TI-83+. If she had a 50g and had a problem during a test, then she would be SOL. No other 50g around to borrow, no teachers for help, no peers for help. My kid's future could be at risk.

The best solution is usually the best supported (vendor, software, peers, community, etc...) solution, not always the best technical solution.


Both my sons used their HP48GXes in high school, and both were the only ones in their classes with an HP of any kind. Neither had any problem adapting the TI-centric instructions and examples in their textbooks to their HPs.



... but I do not like TI.

Have a closer look at a Ti84, Ti89 or Voyage 200 (or the new nSpire, once it becomes available everywhere) and you may change your mind, much as I did mine. Ti have produced some, let's call them 'inferior', products (especially regarding the keyboards!) in the 70ies and 80s, but those times are long over. There is presently no hp graphing calculator that comes close to the current Ti products in terms of build and keyboard quality, functionality and IO/connectivity. The Ti-GraphLink software also runs on MacOS which alone would be reason enough for me to choose Ti...

Second hand Ti graphing calculators can be found on eBay in large numbers and it should not be difficult to find a good '84 for less than 50$/Euros and an '89 or Voyage for less than 100. (I paid 70 Euros for my Voyage 200 with graph-link cable included).

Greetings, Max


I think the TI calculators have terrible keyboards. It feels like you're pressing them into oatmeal or soggy cardboard. I don't know how that qualifies as quality, especially compared to the HP-50g...

The TI-84 has the same interface as the 83, which is amazingly unintuitive to anyone. And the Voyage 200 isn't allowed on many standardized tests, at least in the US.

If you'll go with the 89, then your son probably won't be able to follow along key-for-key with the class, so there is no particular reason to choose a TI over anything else.

No idea how a HP-50g doesn't match on functionality with, as you listed a TI-84....? Seriously?




No idea how a HP-50g doesn't match on functionality with, as you listed a TI-84....? Seriously?

Of course, you cannot compare the hp-50G to the Ti-84. The hp-50G is a competitor to the Ti89/Voyage/nSpire. About standardised tests in the U.S. I know nothing, but they were not mentioned in the original posts.

Here in Germany we don't have much choice anyway, because it is the school who decides which calculator or CAS is to be used (and novadays, they even provide them for the students much to the annoyace of my wife, an arts teacher, because the costs involved are taken away from her budget).

Greetings, Max


If he'll continue in math through highschool or college, he would be best served with either a TI-89 model, or an HP-50g. If the school is suggesting a lower TI model than that then he'll want to upgrade in the future anyway, so why not get the TI-89 or HP-50g now?

Some will argue that getting a TI-83/84 is good because "everyone else will have it", but I found that not to be the case when I was in school (graduated high school in 2002). In lower level classes, the functions used are pretty limited, and finding them on the 89 or 50 is straight forward. I'd say I didn't miss any educational benefit by not being able to type "yellow button, window button, five button..." with the teacher.

As to which between the HP-50g or the TI-89, I'd certainly recommend the HP, but that's me. Which ever one he can get interested in enough to learn for himself would be the best. Beyond the interface, he won't run into the technical limitations of either (really I mean the TI) for quite some time.

That's my take on it, anyway.


If he'll continue in math through highschool or college...

Well, he is a sophomore in high school and he wants to go to MIT when he goes to college. He is interested in computer science, so I think he will need a good calculator, but I don't see the need for graphing calculator in real world.

Well, I still puzzled as to what to do.


If the school recommends TI, it is probably because the teachers are using TI and can give support. HP may be technically superior to TI, but take my word for it (as a middle school math teacher), if he can't get something to work and he has an HP, no one at the school will be able to help him. I've only met one public school math teacher who even knew what HP stands for, and even he used TI in the class. Face it, TI has that market locked up, and the TI-83 and 84 are not bad calculators and graphers.


If he is willing to learn how to use the calculator then the 50G is good. I don't see any advantages from the 49, 49G+, 48GII. The 48GX may have some advantages over the 50G but it's no longer available new. But then the 50G has a lot more functions than the 48GX. However, I found that most students don't care to learn how to use their calculators and in such cases it's best to buy what the school recommended. To many students nowaday, calculators are just the neccesary evil. Something they must have but they hate them.


And to think I went to Technical University of Budapest (BME) with a slide rule. I just shake my head that students need calculator in high school. Students NEED to understand how to do math, and how is calculator going to teach them that? Calculator necessary after you understand how to do math and it makes things solve quicker, but that should not be concern until in college.

We have saying in Hungary, Nem akarasnak nyoges a vege, which means laziness brings struggle. Maybe I to old school, but I do not want Dezso to struggle like I have. I shall see. Maybe I give him slide rule and graph paper and say that is 100% Hungarian graphing calculator. Ha-ha, I think he would not like me for doing. :)


Hi Vincze,

I am a long-time high school physics teacher and long-time HP calculator user and fan. My school also strongly recommends TI graphing calculators and it has been years since I saw a student carrying an HP. So I have been forced to learn how to use TI calculators and I am very familiar with the graphing models and spend a good deal of class time interacting with students as they use TI calculators. In the meantime I refuse to stop using HP so my students must think I am a freak (and are sometimes a little in awe) when I am brandishing my 48g or 49g+ (or soon my 50g).

On TI calculators: Over the years I have come to respect TI calculators. These are reliable, well designed machines. I believe TI calculators are easier to use for graphing than HP. The programming languages are fairly complete and easy to use - very similar to BASIC. In my mind there are really only a couple of disadvantages. The buttons are indeed "mushy" in a sense, because there is no "click" or "tactile feedback", if you will, as on HP models. On the other hand, I have never seen a TI graphing calculator that missed key strokes or doubled them as some recent HP's have been known to do. The biggest disadvantage to TI in my mind is the reliance on parentheses to enter complex calculations - I see it all the time, students missing problems for lack of or misplacement of parentheses.

On HP calculators: As I mentioned I am firmly an HP fan. (I may be unusual because I can find merits in TI.) Advantages for HP are the opposite of the disadvantages for TI mentioned above; the tactile feedback of the keys and RPN (or RPL) entry. In particular, based on your comments about truly understanding math and an interest in MIT, I would think the "HP way" would be desirable. As you probably well know, when solving a problem with RPN you must think about order of operations, you can see intermediate results, and you do not need parentheses. This forces one to really think about what the calculator is doing. The programming on HP is very different from TI. It is not BASIC but rather RPL, which is very similar to RPN in that you basically mimic the keyboard strokes that you would press on the calculator to achieve the desired result. One disadvantage is the rather steep learning curve for recent HP graphing models and lack of a comprehensive and well written manual. Also, as implied above, working with graphs is a bit awkward and counterintuitive (I hate to say it but I usually grab a TI if I need to do some graphing).

Now a few particulars. The TI 83/84 line is easiest for most students to use and these are solid well established calculators. The TI 89 and HP 49/50 calculators are tougher to learn how to use and also have Calculator Algebra Systems (CAS) that can solve equations, derivatives, integrals, series, etc. (Something I suspect you would frown upon based on your comments.)


Good morning Matthew. Would you tell me more about the calculator algebra system? I have not heard this before.

Also, I looking online to maybe get a used 48gx. Is this good HP or would the 49 or 50 be better for Dezso?


CAS allows for symbolic solutions and manipulation of equations and algebraic expressions. For example type in equation 3x^2-7x=17 and tell the calculator to solve for x and you immediately get both solutions x=-1.484..., x=3.817... Or, enter ax^2 + bx + c=0 and tell the calculator to solve for x and it will return the well known quadratic formula: x=(-b+-sqrt(b^2-4ac))/(2a). And the ability to solve is not limited to polynomials. Likewise the CAS will "do" calculus and give numeric or symbolic derviatives, integrals, series, limits, etc.

The reason I mentioned it in the context of your original post is the potential impact of CAS on students. Here are my observations from the classroom. Students get in the habit of using the CAS to solve equations. It really is a very powerful tool. A common problem in physics is solving an elastic collision using conservation of momentum and energy which results in a nonlinear system of equations. The student with CAS can get the answer by simply typing in both equations and which two variables to solve for! I often accuse my students of becoming SOLVE addicts! (the name of the function on the calculator) Through all of my AP Physics C course (equivalent to 1st yr college) there are only one or two algebraic problems that CAS cannot solve. Likewise with the calculus problems in that course. Keep in mind that I teach a physics course, not algebra or calculus (well, yes physics IS all that too) so I don't really have a problem with students using CAS; I require them to show work. Also I think my best students are as good or better than ever, in spite of being SOLVE addicts.

However, I would think that CAS could indeed be deterimental in algebra or calculus classes - especially if the student is not disciplined enough to refrain from using it while doing homework. In this regard HP may have a slight advantage simply in the fact that its CAS is a bit harder to learn and harder to use than TI's CAS. I can imagine a student getting an HP 50g not really understanding all that it can do until several years later when the use of CAS is more appropriate.

As far as 48g vs 49g vs 50g (I have owned all three - just got my 50g the other day), I would just go with the 50g. It does everything that 48g does and more and it has a much better LCD display. Yes the original 48g is probably a little bit better made and has the big ENTER button . . . things that are more important to a long-time HP enthusiast than to today's students (it would seem to me).


Does 48gx have CAS? I found someone I work with who own one and is willing to sell me it. He say I can buy for $50. Is that good price? He no have books, but I find online someplace and make my own.

I too worried that Dezso might "cheat" and use CAS to solve those type of equation. As me say before, I believe student should know math first by doing hard way, and avoid laziness (laziness lead to struggle). I do understand what you say though that it is not an issue since you teach physics and not math. I guess that go along with saying of use all tool available to you. In life, I use slide rule in college, but in work world I no longer use slide rule, I use calculator or computer as those tools available to help me.

Maybe I look at 50g. I think it ugly looking. 48gII look nicer, but looks not calculate. I think they all very expensive though.

So sorry for my bad english.


48GX does not have CAS; however the CAS for the 49G was developed from programs written for the 48GX as an independent programs: Erable and ALG48. Furthermore the shell in the 49G (and the later 50G) came from "Metakernel" which was also developed for the 48GX (by Jean-Yves Avenard).

If you buy two ram cards for the 48GX, you can load Metakernel, ALG48 and Erable as well as other stuff and you have the supercharged CAS-enabled 48GX.

BTW $50 for a 48GX is a very good price.

The software is all free and available here:

Edited: 31 July 2007, 12:47 p.m.


Good afternoon Bill. Thank you for the information. Where can one find memory card? How much should they cost? Wife very money conscious and say I adopt American spending sickness, more I am in this country. I tell her I *am* American, so this good I have sickness. Although, this calculator for our son, so I have good excuse here to have American spending sickness.

Also, is CAS what they also say "textbook entry"? I think I understand what CAS might be, but it seem like it is a program to isolate variable, and also other thing.


Holy Wow... I pay co-worker for 48GX yesterday and he bring in today. Wow... this monster calculator. He did find one of book. I think you need PhD to understand this calculator. I can see why student may have trouble with this. He even show me that it have mine sweeper, and way to enter equations graphically. That very cool. It seem very hard to use though. Is 50g easier to use that 48gx?


I would highly suggest taking a look at Thomas Barber's guide to the 48-50G series, The Definitive User's Guide to the HP 48g/49/50g Calculators. You can find this on the Sampson Cables website.
For the price, this is one of the best explanations and guides to using this series of calculators.
I would say neither the 50g or 48g are harder to use than the other; they have different approaches to certain types of problem entry, but both are outstanding RPL machines. I prefer the 48g series due to the well-placed ENTER key and the key pad layout and feel.

Edited: 2 Aug 2007, 10:29 a.m.


The 50G is not fundamentally different to use than the 48G--the 50G uses the same RPL language and paradigm.

The "quick start guide" is also good to read, as well as the original manuals. You can download them from HTTP://

IT is RPL not RPN, so there are some small differences (such as if you want to SWAP the 1st two levels in the stack, you have to first ENTER to put the command line into level 1.)

You can make algebraic objects by typing the ' character first. The algebraic object lives on the stack, can be duplicated etc. If you push EVAL it will be evaluated....

You can save to variables, for instance:

123 ' [alpha alpha] VAR1 ' [alpha] STO

This will store the value 123 into a variable named VAR! into the current directory.

You can recall this variable. You can use it in algebraic objects or programs. The variable can be an equation or a program etc...

Edited: 2 Aug 2007, 11:33 a.m.


Good afternoon Bill. Thank you for the information. I am a bit confused at RPL as I have never seen it before. I was looking for R/S button for awhile, and then someone told me that there was not one because of RPL.

I like the fact that assigning variables is that easy, and it seem like RPN is there in the background with doing math.

I looked on the HPCALC site and did find the books. Thank you. The one came with the calculator, but the advanced one I do not have so that will help.

Is there something that describe main difference between RPN and RPL, like a short dummies guide? I know there must be quite a big difference, but it would be nice to see the main points.


Read the RPL page:
Read the 48GX documentation:
You'll also find a 48GX emulator helpful: (Windows) (Mac - old) (Unix/Linux)

There might be a guide for when the 28c was developed.

RPN = Reverse Polish Notation
RPL = Reverse Polis Logic (or Lisp, or...?)

RPN is an input paradigm, of which RPL is related, but RPL is also a whole programming language.

feature                 rpn                    rpl
stack x,y,z,t; t replicates cmd line, 1,2...infinite

registers STO RCL to ltr or # true named variables

Programs dedicated line interpreter Programs are merely
in its own logical space items on the stack,
separate from GUI saveable like any
other variable.

Edited: 2 Aug 2007, 2:48 p.m.


As always, Egan and Bill, you are very helpful. Thank you!


I can't figure out the programming language on my TI83+ to save my life, but I must admit the thing has grown on me for some things. The pretty fast and accurated Gauss-Kronrod integrator is superior to the Romberg routines found in HPs, up to and including the 35s, and sort of impressed me.

Maybe when he can more easily afford it he will have some choice--the calculator he must have in order to jump through the academic hoops, and the one he really would like to use just for himself.

As for further comments in this thread about calculators in math education, I must admit I struggle with this one. I love calculators, have since I was a kid and got some Novus 4-banger, now long broken and lost. But I at some point learned long division, multiplication, and addition of sums--heck, even square roots, but I can't remember the algorithm any more--with pencil and paper. So for me electronic calculators have never seemed a crutch or the lazy way. But I know my experience is exceptional. I have heard stories from teachers that every calculator in the class comes out when the kids are called upon to compute the simplest sum as part of an exercise.



Today any calculator can be had for less than $200 (except them collectible HP's), so the issue of affordability is not there.


Good afternoon Les. I agree with you that a calculator is needed in the real world, but children need to have experience and exposure to numbers to they get a sense of number familiarity. They will develop recognition of patterns by doing math by hand. In fact, Dezso can very quickly find the square root to four decimal places very quickly (as can I). You say you do not remember algorithm no loger for finding square root, but it is so simple. All you do is estimate the square root to at least 1 digit, then divide this into the number whose square root you want to find. You then find average of the quotient and the divisor, and the result is your new estimate. When I learn this many years ago it was called the Babylonia method and is truly very quick.

For example... let's try and find square root of 30. With calculator, I can see that it is 5.4772, but using my method here is how you would do. Let's make our first guess 10. We take 30/10 = 3. We then take (10+3)/2=6.5 Now we use 6.5 as new guess, and 30/6.5=4.6154. Get average of (4.6154 + 6.5)/2=5.5577. New guess is 5.5577 and 30/5.5577=5.3979. Average of (5.5577+5.3979)/2=5.4778. Use new guess 30/5.4778=5.4767. Average of (5.4778+5.4767)/2=5.4772. And there is our answer. Yes it take a four guesses, but in four guess I have it to four decimal places.

I bet you ask child in school now, and the have no idea how to figure square root without a calculator. Maybe I am wrong, my myself and wife teach Dezso how to do this in 4th grade and he caught on very fast because it just use simple addition and division.

I not try and knock people cause they use calculator, as I use too, but I more concerned of children not understanding basic knowledge of math and I think that put them at serious disadvantage. I know I sound dumb because I no have good english skills, and that ok, but I want my boy to be smart, like me, even though I speak badly.


Les, it's just BASIC! Instead of typing the commands, however, you insert them via a menu, just like many systems. But it's actually much easier to write the BASIC code on the PC using TI-Connect software (which has always worked flawlessly for me) and then download it to the calc.

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