Ask HN: Should there be new RPN calculators to replace the TI-84?

I took an exam today where only TI calculators were available. I felt I was caught between some older models where the TI interface was not quite worked out.

And I don't see much progress then trying my daughter's TI-84.

28 points | by idatum 4 days ago

28 comments

  • inejge 4 days ago
    Calculators, especially scientific and graphing calculators, are a niche product these days, almost exclusively limited to education and exam-taking. There is no impetus for changing the approved models, given the mountains of materials adapted to their use (TI actively worked with various educational bodies to promote the use of graphing calculators and helped prepare the curricula using their own.)

    Don't expect great changes in this area, although the impending death of the Dept. of Education might shake up things. Not for the better, I think.

    • zokier 1 day ago
      Education seems to be moving to computer based systems like GeoGebra and Desmos. So the market for separate calculators is becoming even more niche, mostly just die-hard fans who'll get stuff like SwissMicros devices
    • lo_zamoyski 1 day ago
      > the Dept. of Education might shake up things. Not for the better, I think.

      Given how mediocre and even harmful public education in the US is, especially relative to its (now waning) superpower status, how large the US is, as well as the promotion of weird ideologies by the DoE, I cannot help but welcome its death. In general, I welcome to end of all sorts of vast educational bureaucracies, including those that have occupied private universities and drain them of resources without providing any justifiable benefit.

      I think this is where people don't grasp that we didn't always have the kind of overbearing, cabinet-level department of education we have today. This really only goes back to the early 80s. Meaning, opposing the DoE isn't the same as opposing education. The principle of subsidiarity ought to be respected. Decentralization is good. It should be liberating.

      So, in practice, I anticipate a greater diversity of curricula. There already exist competing views on pedagogy. This would allow greater flexibility and educational liberty, but also the opportunity to observe how well various pedagogical approaches work. It also introduces a certain accountability, because while you can blame mediocrity on a distant DoE today, the responsibility for education will lie closer to home when there is no DoE to blame.

      Incidentally, people like Feynman ostensibly lamented that he expected physics to stagnate given what he saw as the homogenization of education. A similar principle could be said to apply here.

      • motorest 14 hours ago
        > I think this is where people don't grasp that we didn't always have the kind of overbearing, cabinet-level department of education we have today. This really only goes back to the early 80s. Meaning, opposing the DoE isn't the same as opposing education. The principle of subsidiarity ought to be respected. Decentralization is good. It should be liberating.

        You dumped a lot of vague buzzwords but you said nothing of substance. You oppose DoE? Why, exactly? It's not clear. If you cannot even express why exactly you oppose the DoE, what does decentralization mean, and why do you believe that to be liberating?

        There seems to be a segment of the US population that was heavily indoctrinated into an irrational belief that having any guidance at the federal level is inherently a major problem.

        In the meantime, back in reality, the main responsibility of the DoE is to fund scholarships and schools from districts that are unable to self-fund. That's what you get rid of when you argue for getting rid of the DoE. Why is this liberating?

      • scythmic_waves 23 hours ago
        > as well as the promotion of weird ideologies by the DoE

        What weird ideologies?

        • gperkins978 20 hours ago
          That rabbit hole will make you angry, then sad, then hopeless. I live in Chicago, on the South Side. The number of foolish fads in education have been forced on poor children for decades. It is shameful. Children should not be experimented on because their parents could not afford Catholic school or a house in the suburbs. Rich white people enjoy warping the minds of black children far too much. They never experiment with their own children, only ours. It is sickening.

          An example: https://www.insidehighered.com/news/quick-takes/2023/09/08/c...

          https://www.nytimes.com/2022/05/22/us/reading-teaching-curri...

          • tptacek 8 hours ago
            These programs were in place in D97 in Oak Park, a wealthy and predominantly white suburb, too.
          • umbra07 17 hours ago
            I don't see how the DOE promoted this woman's style? It seems like cities and districts independently chose to adopt her methodology.
  • seoulbigchris 1 day ago
    Back in college one summer, I had an HP calculator crammed full of programs I had written for various circuit and RF design courses I was taking. I didn't have any way to store them, other than writing them down on paper. On a whim that summer, I went to take the Ham Radio Extra class exam one weekend. The proctor said I needed to erase all the memory from my calculator before using it on the test. I told him no way was I going to do that, but suggested an alternative.

    I had been curious how slide rules worked, and had found one after searching high and low for in half a dozen stores before finding probably the last one for sale in Atlanta. The slide rule was in my backpack, so I asked the proctor, could I used the slide rule instead? He chuckled, and said no problem. During the test, one of the proctors tapped me on the shoulder and asked me if he could bring me a bucket of water to cool down my "slip stick". I did pass the test that day, and I used to brag that I got my Extra Class license with a "Slide Rule endorsement".

    • 0xfaded 1 day ago
      I'm a for-funsies pilot and I took my most recent exam with a physical EB-6, which is a circular slide rule of sorts. Of course the way people take these exams these days is to just to memorize all the questions. The FAA hasn't seriously updated the question bank in years and there are known wrong answers in the answer key.
      • theflyingelvis 22 hours ago
        The E6-B is what I took my exams with too! But, that was ‘several’ years ago.
  • Suppafly 2 days ago
    >Should there be new RPN calculators to replace the TI-84?

    I'm not sure I really understand your question, TI-84 (and all other TI models) don't use RPN. You can run a program to allow RPN input you want, since most of the higher TIs are programmable. I believe some of HPs current lineup have a limited RPN mode available and SwissMicro makes some new RPN calculators.

    >I took an exam today where only TI calculators were available.

    That's common as they are the ones used to teach math classes and are vetted to prevent cheating on standardized tests.

    >I felt I was caught between some older models where the TI interface was not quite worked out.

    I have no idea what this is supposed to mean.

    >And I don't see much progress then trying my daughter's TI-84.

    Nor this.

    • selimthegrim 1 day ago
      Having been the proud owner of a TI-82 myself I can only surmise this guy has no idea what RPN means
    • widforss 1 day ago
      HP 50g is "modern" and has RPN out of the box, I use it regularly.
  • linguae 4 days ago
    There are some RPN calculators from SwissMicros that are inspired by HP’s RPN calculators from the 1980s and 1990s:

    https://www.swissmicros.com/products

    There is also the HP-15c Collector’s Edition (I have one), which is still in stock: https://www.thecalculatorstore.com/c/hp15c

    Two caveats:

    1. These RPN calculators are not cheap.

    2. Many standardized tests have lists of approved calculators, and it’s possible that the calculators I mentioned might not be on the list. TI has dominated the education market in the United States for the past few decades, and even during the heyday of HP’s RPN calculators, HP largely focused on engineers and other professionals rather than education. Thus, you may need to buy a TI calculator for exam purposes.

    I love RPN calculators: I have a HP-48X that I bought used on eBay nearly 20 years ago when I was an undergrad, and my aforementioned HP-15c Collector’s Edition. However, these are collectibles for me; as a computer science professor I’m always in front of a computer, and thus I have access to the Unix dc command whenever I need an RPN calculator, and for more complex computations I have my choice of Excel and various programming languages.

    • slowhand09 1 hour ago
      I've long been a fan of HP Voyager series calculators. I used an HP-11c daily at work years ago. I still have it, an HP-15c, and and HP-12c. The 11c and 15c are both probably still on their 2nd set of batteries, after 40+ years.
  • jqpabc123 4 days ago
    Not what the OP asked for but related.

    The link below is for a near perfect simulation of the classic HP-15C RPN calculator. Works on both desktop and mobile.

    In a former lifetime, I was an engineer. I bought one of these in the early 1980s and used it for almost 40 years before the screen died. Very popular among my colleagues at the time.

    https://jrpn.jovial.com/

    • y33t 1 day ago
      If you want a native options on a mobile device, Free42 and 48sx work great on Android (I believe at least Free42 is on iOS). Emu48 works on desktop (personally I like `dc`). Look at SwissMicros if you want a physical calculator.
    • sloaken 3 days ago
      That is awesome. Thank you for posting this.
    • dwighttk 1 day ago
      Need to find one of these for hp32SII
  • donatj 1 day ago
    As a Middle-Aged person who does math on the periphery of calculus reasonably often, for work and in my day to day life, my irritation with calculators is that their capabilities are largely driven by the education markets demands. The small handful of calculators with CAS abilities are usually kneecaped to what would be allowed in a testing environment.

    I want a calculator that can do all the transforms for me and show the work so I know what I'm doing.

    For my day-to-day needs I literally run a TI-89 emulator on my android phone these days. Seems silly.

    • zokier 1 day ago
      Mathematica?
      • gperkins978 20 hours ago
        My thought exactly, or Maple, if you are one of THOSE people.
      • donatj 20 hours ago
        It's a lot of money and isn't a standalone device.
  • charlieglass 1 day ago
    Swiss Micros have some fairly decent recreations of HP's greatest hits. Pricey, but I am going to get myself one for my birthday. https://www.swissmicros.com/products
    • y33t 1 day ago
      I have several of these and I'm really impressed with the quality. The DM32 is nice and has a manual available from SwissMicros, but I prefer the DM42n. I had a print shop print and spiral bind an HP-42 manual for me. Works good.
    • bluGill 1 day ago
      Inflation adjusted they are cheaper than the HP they are recreating. Even if you don't adjust for inflation they are competitive to the old HPs in the 1990s.
  • aforwardslash 4 days ago
    Have a look at https://www.numworks.com a easy to use scientific calculator that is opensource
    • varun_ch 3 days ago
      As a high school student I can’t recommend the NumWorks enough (but you will absolutely find it lacking if you need it for anything other than high school maths).

      It’s a really nice tool (although not an RPN calculator). It’s like if Apple designed a calculator… very intuitive.

      That said, I wouldn’t call it fully open source. They had some issue because they released an update that locked down their calculators to satisfy school boards (because otherwise students could modify test modes to cheat on tests). The software on GitHub was also out of date, last time I checked.

      • donatj 1 day ago
        I know they removed the CAS capabilities to appease school boards. Are you still able to replace the firmware with the CAS capable version?
      • aforwardslash 3 days ago
        Good to know, while I had purchased one for my daughter, I had only a cursory look at the released files.
    • nbernard 3 days ago
      Not really true anymore unfortunately: The latest models (post-2020?) are locked down and cannot use non-official FW.
  • RandomBacon 4 days ago
    I had to look it up:

    RPN = reverse Polish notation

    https://en.wikipedia.org/wiki/Reverse_Polish_notation

    • pulvinar 4 days ago
      Wow. In my day it was well-known. HP calculator ads in magazines explained RPN and why it was better.

      "Magazine? Had to look it up."

      • pavel_lishin 3 days ago
        I did UIL competitions in Texas in the late 90s and early 2000s, including calculator competitions.

        That's the only place I've ever heard of RPN, which is what nearly all of the winners used, and which we learned to stand a chance.

        • dwighttk 1 day ago
          I waddled into my first UiL calculator test because the sponsor wanted to get more team members and spent most of my time blown away watching kids entering problems into two calculators simultaneously
      • technothrasher 1 day ago
        When I was in high school in the 1980's, the other students knew RPN only as the reason they couldn't borrow my weird calculator.
    • themadturk 18 hours ago
      I am a decidedly non-mathematical/non-engineering person, but have loved RPN calculators since I bought an HP back in the mid-1970s. RPN is just natural to me, even doing basic arithmetic. I use PCalc in RPN mode on my iPhone.
  • simne 21 hours ago
    I have used Soviet RPN calculator at my school years. It was not compatible with TI or something Western, but as I know ideologically it was very close.

    What also interest, in early 2000s, Russia made modern remake, with much improved performance and added digital i/o, and compatible with old programs (even emulated some old glitches), so it could really run tons of programs one could find on old books/magazines.

    I could not recommend anybody to buy Russian calculators, just want to say, this is very significant niche (RPN), but hugely depend on compatibility (with old software and old books) and on nostalgia.

    https://en.wikipedia.org/wiki/Elektronika_MK-61

  • ChrisMarshallNY 1 day ago
    I think there may be some confusion about "RPN" (Reverse Polish Notation). It was very popular with certain folks, Back In The Day, but I, personally, never warmed to it. I don't think it ever would have been mandated for tests. It was very much a "deep geek" notation.

    But if you really want it, and are an Apple user, I have found that the PCalc app[0] has been excellent (I've used it for over 30 years). It works on multiple (Apple) platforms, and has RPN (the real RPN) built in, as a selectable option.

    I suspect there's similar apps for Windows, Linux, and Android.

    [0] https://pcalc.com

    • scblock 23 hours ago
      PCalc is indeed excellent.

      As for RPN, it's one of those things I didn't get until I was in my 30s and started using it. Then used it more. And now I'm at the point where using a "normal" calculator is a frustrating experience. I got very used to the stack and having intermediate results. I find it highly frustrating that the windows calculator still doesn't have it as an option, and that when asked about it the developers seemed confused why anyone would want it.

      Free42 has filled the gap though.

  • rightbyte 4 days ago
    TI calculators are not RPN. I think HP made (makes?) RPN calculators.
    • timcobb 1 day ago
      Yeah, I'm also confused by this... the only RPN calculator I know of is the HP 15C, which is old school and not used in education.
      • rightbyte 1 day ago
        I bought a HP50 (?) in uni to do symbolic math for some exam. It was RPN by default but you could switch.
      • kube-system 1 day ago
        > HP 15C, which is old school and not used in education.

        Business courses frequently use it

      • JackFr 1 day ago
        You still see some HP12Cs on bank trading floors.
  • gperkins978 20 hours ago
    I used the TI-85 back when dinosaurs walked the earth. I still have that and the TI-92, the best FAT calculator ever. This thing will tie your shoes and help fight off depression. I strongly recommend the TI-92. It is not allowed on any standardized tests though.

    I do know that even my TI-85 was programmable. I made a few different functions with it. If you try anything too sophisticated, there really is not sufficient space for it, but it was the first device I ever wrote any kind of program on. I used that through university, but for work I had the HP 12c with reverse Polish notation. Now that was useless. I could never understand why old men preferred that to Excel. Excel is better in every way, and one can write pretty sophisticated functions and simulations in Excel VBA. I spent years doing so.

    Overall, I do not see the point in bringing out new calculators. I do think the existing ones should have more RAM and storage with a bit more computational heft, but only 1-3% of owners are ever going to use that, but it will make them so much better.

  • drvladb 4 days ago
    The HP Prime, though pricy, supports a decent RPN mode. Definitely for a higher level of education (CAS, programs, all that fun stuff), but approved for a decent amount of US based exams.
    • leejoramo 2 days ago
      Pricy is relative. Looks like Amazon sells it for $125 (the SRP is $230)

      As an engineering student in 1987, I bought a HP-28C. I recall it was the first calculator to do symbolic math

      Original Price $235 which is close to what I paid. Adjusted for inflation $657

      I think it was worth it.

  • RecycledEle 4 days ago
    Even 7th and 8th grades use TI Nspire CX calculators in my area.

    As rightbyte said, RPN is an HP thing, so if you want an RPN calculator, ask for an HP. Most test administrators can help you.

    • Suppafly 2 days ago
      >RPN is an HP thing

      Not anymore, that's why older engineers pay inflated prices for old ones on ebay.

  • JumpCrisscross 21 hours ago
    “TI’s calculator ecosystem facilitated a needed educational reform and created training resources for math teachers. Its emergence as a national standard simplified math education, reduced teacher training costs, and contributed to teacher job mobility. Educators, who may have taught for decades, even preferred the lack of innovation. Additionally, students have been able to take standardized tests and enroll in STEM courses in college without needing to switch calculators.”

    https://www.promarket.org/2024/04/08/tis-calculator-monopoly...

    (Also, TI supports RPN. It also supports PN and infix notation.)

  • jasonthorsness 1 day ago
    So far my son (8th grade) really just uses Desmos https://www.desmos.com/calculator which is apparently also built-in to the SAT now (which is taken on a computer) - I have been trying to convince him a separate calculator is better but so far no luck.
  • parsimo2010 1 day ago
    IMHO we'd be better off focusing on policies that allow computers to be used on standardized exams. Hardly anybody uses a calculator in a real job, people at desks use computers, and even people who have to do calculations in a field environment use ruggedized tablets. Rather than working on revamping obsolete technology we should work on a way to make a computer acceptable to use on an exam in a way that addresses cheating concerns.

    But if you really wanted to keep using a calculator, you should check out the HP Prime, Casio Prizm, or TI-Nspire series. The HP Prime has RPN, and all of these lines have color touch screens and a bunch of modern features. The TI-84 is not the pinnacle of technology, it is popular only because it is an exam-acceptable and an old standard format that people are used to.

    • ielillo 22 hours ago
      From my college experience I never needed a Ti or Hp calculator. Most of the questions did not require anything more complex than logarithms, exponential, root and trigonometric functions. A good question should be about concepts, not results. I remember a linear algebra test in where you had to solve a problem by inverting a matrix to get a result, the problem was that the matrix was so large that it could have taken the entire test time to get the result if done by hand. However if you were clever, and knew the matrix properties being tested, the matrix could be simplified and the result gotten in 3 steps. If you had a Ti or HP you could have entered the matrix and get the result, but the question would have lost its meaning
      • gperkins978 20 hours ago
        For many business-type courses they like you to be able to quickly get an IRR or NPV value. One could solve that by hand, but the exams would be long and require manual grading. According to my older colleagues when I started my career, they used to bring their HP calculators to client meetings before laptops were a thing. They would sit around and do estimated calculations. If you look at old photos, your can see the HP calculators in them and paper with written calculations. When I started my career in 2000, laptops were already ubiquitous. There were still old timers with the RPN calculators from HP. Excel is better for finance. For real analysis and simulation stuff like Mathmatica and Maple are better, with SAS, SPSS and R for statistics, although SAS is used a ton in finance, insurance as well as government.
        • ielillo 18 hours ago
          That's another point, during college some tests were and multiple choice questions. They were manually graded and for each answer you needed to prove how did you get the answer. I don't remember any kind of automated grading system. Everything was done by hand, whether by the teacher or TA's
    • bluGill 1 day ago
      What are you testing? I found in math that my test scores went up when I quit using a calculator. All the exam questions were carefully designed to make the arithmetic easy if you did it right. Thus anytime the arithmetic looked hard I knew to start over and find/fix my mistake.

      In physics that didn't always apply, but it did often enough that I didn't pull out my calculator until after double checking that I was sure I did all the steps right.

      In engineering classes the math was never easy. In the early classes you should still use a basic calculator though as the point is to understand the math behind the problems. In latter classes you can be assumed to understand that and computers to do all that complex math while you focus on the large problem might be good.

      • parsimo2010 23 hours ago
        OP's question wasn't about whether they should use a calculator on an exam or not. If you can trust that an exam has questions crafted to have integer answers and completed only with basic arithmetic, then use that strategy by all means.

        OP's question was whether or not there should be replacements for the TI-84, and mentioned that this question arose from an experience taking an exam. Aside from the fact that they may be confused about what RPN is, I suggested that I would consider the use of computers a better focus for exams rather than getting a replacement for the TI-84. And aside from that, there are already replacements in the forms of new calculator product lines.

        • bluGill 23 hours ago
          The correct answer depends on the exam's goal. If you want to verify understanding the fundamentals, then a pencil and paper is all you should get. However that limits the complexity of the problem you can be asked. With a calculator you can do more complex problems - but the tool will do some things for you and so if you get the answer wrong there is no way to know if you failed on the fundamentals (you need to drop out of this class and be send to the lower level one) or the complexity (stay in this class).
  • cameldrv 1 day ago
    I still have my old HP48GX, but I find I use iHP48 more often because it’s much faster. I had a 49G also but the keyboard died just from sitting in a drawer… the HP build quality took a nosedive in the late 90s.
  • tgv 1 day ago
    RPN is not a good fit for the classroom. It doesn't connect to the way math and arithmetic are taught, since ages. RPN comes from the days when parsing an expression in a calculator was hard. I've got a two RPN calculators at home, and I think it's cute, but it's a nerd thing.

    If you want a non-TI calculator that's allowed in the classroom: look at the Casio and Numworks.

    • upghost 1 day ago
      I use numworks frequently these days (as a software eng just need to do some quick math and not worth writing code or spreadsheet for, not talking about student use). I bought the thing but they have a free phone app too, works exactly the same.

      I can't ever remember how to use my TI-89 but the numworks is pretty intuitive

  • SAI_Peregrinus 1 day ago
    There are RPN input programs for the TI graphing calculators.

    There are RPN calculator apps for phones (I like RealCalc on Android).

    There are RPN calculator programs for computers (I like Qalculate for GUI, Orpie for a terminal).

    There are emulators for the old HP RPN calculators.

    Physical calculators are pretty much only useful for situations where internet access isn't allowed, like some exams in school.

  • HachiWari8 2 days ago
    The DB48X project looks interesting: https://48calc.org/
  • leros 1 day ago
    The only real place I've seen RPN calculators used post-2000 is in calculator competitions (oh yes they exist)
  • showdeaduser 3 days ago
    No. They're all ganked to be permitted on standardized tests anyway.
  • oneoverten 2 days ago
    What is lacking from the TI-84? Why do you specifically want RPN?
  • dwighttk 1 day ago
    Not sure I remember my TI-84 being RPN
  • johnea 21 hours ago
    I'm still more of an HP-41 fan.

    In addition to having several of these, I also use this desktop emulator:

    https://nonpareil.brouhaha.com/

  • lo_zamoyski 1 day ago
    The TI-84 is not an RPN calculator. But what would be the advantage?

    And what is this "progress" you speak of? Frankly, I don't know that these calculators should be used in instruction anyway. It smacks of attempts to "modernize education" by throwing computers are it, without justification. Why? Computing devices have their place, but their utility is practical, and their pedagogic value in primary education is limited to specific applications. Using them to teach math seems off. You shouldn't be wasting time on things that have little educational value but that would require a computing device to expedite tedious work.

    • gperkins978 20 hours ago
      If you want to get REALLY angry, go to school in poor neighborhoods and watch teachers "teach" children how to search the web. Computers in schools was a mistake. If there were to be computers, they should all be Unix or Linux or BSD distros run from the command line.

      There are key phrases that a school is scam central. Any time they try to say "X percent of students went off to college" that school is a scam. If they speak of creating "computer literate" or "technology literate" students, the school is a scam.

      Check out how easy many of the reading and math tests are, then you will know how horrible it is when schools only have 20-30% of students getting to their grade level. It has been a bizarre transformation where schools went from being oriented around student learning to being oriented around teacher wellness and teacher preferences.

      We should be hiring teachers from Singapore and Hong Kong to fix our schools. Instead we hire creepy education consultants that get rich peddling idiocy. It iw a crime against children.