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

by idatum on 3/9/25, 5:02 AM with 81 comments

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.

  • by inejge on 3/9/25, 11:01 AM

    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.

  • by seoulbigchris on 3/12/25, 2:10 PM

    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".

  • by Suppafly on 3/10/25, 7:37 PM

    >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.

  • by linguae on 3/9/25, 12:58 PM

    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.

  • by jqpabc123 on 3/9/25, 2:35 PM

    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/

  • by donatj on 3/12/25, 2:01 PM

    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.

  • by aforwardslash on 3/9/25, 12:48 PM

    Have a look at https://www.numworks.com a easy to use scientific calculator that is opensource
  • by charlieglass on 3/12/25, 2:00 PM

    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
  • by RandomBacon on 3/9/25, 1:23 PM

    I had to look it up:

    RPN = reverse Polish notation

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

  • by rightbyte on 3/9/25, 9:27 AM

    TI calculators are not RPN. I think HP made (makes?) RPN calculators.
  • by simne on 3/12/25, 6:49 PM

    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

  • by ChrisMarshallNY on 3/12/25, 2:19 PM

    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

  • by drvladb on 3/9/25, 1:18 PM

    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.
  • by RecycledEle on 3/9/25, 12:19 PM

    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.

  • by gperkins978 on 3/12/25, 7:23 PM

    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.

  • by jasonthorsness on 3/12/25, 2:10 PM

    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.
  • by parsimo2010 on 3/12/25, 2:32 PM

    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.

  • by JumpCrisscross on 3/12/25, 6:26 PM

    “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.)

  • by cameldrv on 3/12/25, 2:40 PM

    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.
  • by johnea on 3/12/25, 6:44 PM

    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/

  • by tgv on 3/12/25, 2:46 PM

    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.

  • by HachiWari8 on 3/11/25, 1:14 AM

    The DB48X project looks interesting: https://48calc.org/
  • by SAI_Peregrinus on 3/12/25, 4:13 PM

    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.

  • by leros on 3/12/25, 2:53 PM

    The only real place I've seen RPN calculators used post-2000 is in calculator competitions (oh yes they exist)
  • by showdeaduser on 3/10/25, 9:04 AM

    No. They're all ganked to be permitted on standardized tests anyway.
  • by oneoverten on 3/11/25, 4:34 AM

    What is lacking from the TI-84? Why do you specifically want RPN?
  • by lo_zamoyski on 3/12/25, 3:07 PM

    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.

  • by dwighttk on 3/12/25, 1:46 PM

    Not sure I remember my TI-84 being RPN