# Dorky Poll: Calculators

Over at Cosmic Variance, Julianne waxes rhapsodic about her calculator, a HP-15C. This is such an obvious Dorky Poll topic that I can’t believe I didn’t think of it earlier:

What sort of calculator do you use?

My students, particularly the future engineers, are always shocked by my answer:

I use a TI 30Xa. Actually, I don’t know that off the top of my head– I had to dig it out and look at it to come up with the model number. I think of it as “A \$10 scientific calculator that I bought at Safeway.”

This does everything I need, though– it adds, subtracts, multiplies, divides, does square roots, logarithms and exponentials, and calculates trig functions. It’s also got some statistical functions, but I have no idea how to use them.

Students are forever coming up to me and asking me how to do some operation or another on their huge HP graphing calculators, and I tell them “I have no idea. This is what I use.” They always goggle at me, but it’s the truth– I use a pen and paper to do enough algebra to get it down to where I can keep track of the numbers as I punch them in. I’m less likely to lose my place, or make a mistake, and if I do screw something up, it’s easier to check.

“But how do you graph things?” With a pen and paper. If I can’t sketch a graph, I need a real computer for the job, and I know where we keep SigmaPlot and Mathematica.

“But my HP can do nested parentheses!” La. I can do that on paper. And if the function in question has too many nested function calls for me to keep track of it while entering it into my cheap TI, I need to look at it on a screen bigger than a credit card.

So, I’m all about the cheap scientific calculators– I don’t care if students use the big graphing jobs (unlike my colleagues in Math, who keep a big sack of TI-30Xa’s that they hand out before exams), but I have no interest in using them, or even knowing how.

But enough about my raging Luddite tendencies. What sort of calculator do you use?

## 75 thoughts on “Dorky Poll: Calculators”

1. Ryan Vilim says:

I actually have a TI-83, I was in this program in high school where they required us to buy them. I think this is actually a huge waste of money, I don’t think high school students should be using calculators in calculus, but at the time I was interested in the fact that I could play games on it.

The thing is, that over the years I have just gotten used to it, I like the arrangement of buttons, and the bigger screen means you can see what number you typed in last. That being said, I don’t think I have graphed anything on it in at least 5 years, and even now I rarely use a calculator at all …

2. Aaron Bergman says:

bc or mathematica depending on the need.

Windows Calculator (in scientific mode, natch). If I need something with more firepower, I borrow a TI-80-something from one of the grad students.

Windows Calculator (in scientific mode, natch). If I need something with more firepower, I borrow a TI-80-something from one of the grad students.

5. Uncle Al’s HP-15C has visibly worn key tops. I have been offered \$800 for it (including the manual). FROM MY COLD DEAD HANDS. If you are not smart enough to appreciate RPN then you shouldn’t be trusted with the answer no matter how obtained.

Wincrap has a built-in calculator. Ha ha ha. Perhaps Wincrap Vista has a built-in animated 3-D abacus with skins and a choice of theme music while you wait.

http://www.codehappy.net/calculator.htm
When ya gotta, ya gotta

6. I still have the HP-42S I used in college: http://www.hpmuseum.org/42s.jpg

It’s far more programmable than anyone needs these days, though when I was in college it still made sense and was useful for doing homework. And since I learned to use reverse polish, I never wanted to go back, so I’m glad this calculator still works! Even if I mainly use it for balancing the checkbook. ðŸ™‚

7. Bouncing Bosons says:

Most of the time my number crunching is done by Google.

it’s very nice for not only doing numbers, but automagically changing units too if you’re really lazy

Try searching for (4*pi*electric constant)*(hbar*c)/(elementary charge^2)

If I need something with more muscle (for the ever popular “I really, really don’t want to do this integral”), mathematica comes out.

8. Pam says:

These days, I use the Windows scientific calculator. Back in the day, I used the 15-year-ago version of the Casio FX-260. It is probably still lurking in my apartment somewhere.

I, too, sneer at the ridiculous calculators kids these days use. All issues of “I use my brain for that, kthx” aside, who wants to carry one of those huge things around?!

9. qetzal says:

I use a Sharp EL-546G that I’ve had since college (20+ years now). Doesn’t graph, and I’ve never felt any lack for that. But it does have basic stats, including linear and log regressions, which I use on occasion. It has lots of other features I use rarely, if at all (trig, combinatorics, complex numbers, hex bin dec & oct notations, etc.). It also has a variety of build in constants (e.g. speed of light, grav. constant, Boltzmann, Planck, etc.) and conversion functions (C to F, J to cal, etc.). Those are quite useful to have on hand.

I use it at the lab bench, where it’s much more convenient than a PC-based program (or a book reference, for the constants & conversions). I also use it at my desk for most ‘simple’ calcs. I only use Windows Calculator if I’m at a computer and I’ve left my Sharp elsewhere.

I generally graph in Excel. I use Excel for calculation as well, but mainly if I want to graph the results, or if I want to apply the same calculation to multiple cells.

I almost never need to do any math that can’t be handled by either my Sharp or Excel. And I agree with Prof. Orzel – if I need a lot of nested parentheses, I write things out on paper. Otherwise, it’s too easy to miss a critical close parenthesis and get the wrong answer.

10. Scott says:

I’ve still got my HP-28S from the 80s. Equation Solver got me through a lot. I love this machine and still use it a lot.

I also have a 67 (though the card-reader motor is dead), and 25C and 16C in boxes somewhere.

It’s hard to explain RPN to people who don’t like thinking about math, but at this point it’s natural enough to me that I always mess up anything but the simplest things on “standard” infix calculators.

11. Scott says:

I’m not casting aspersions at anyone that doesn’t like RPN, I should add… just commenting on the uncomprehending faces I’ve gotten from people over the years when I’ve tried to explain how to use it.

12. bcooper says:

I actually have a TI-83, I was in this program in high school where they required us to buy them. I think this is actually a huge waste of money, I don’t think high school students should be using calculators in calculus, but at the time I was interested in the fact that I could play games on it.

I have a TI-82 for very similar reasons. It’s a nice calculator and I certainly got a good deal of mileage out of it, so I think the money was well spent. As far as playing games, this was about 15 years ago, so the games that people ended up having were all ones that we wrote ourselves. That was pretty educational, too.

13. SpotWeld says:

I’ve a TI-81 that I got back in high school that is not in residence at my desk at work. And a slightly more tricked out TI-89 that I got in college for variable calculus. (It’s such a lovely differnetial solver too…)

14. Chris Goedde says:

The 15C was a great calculator. I was very sad when mine gave up the ghost. I have another HP at home (not RPN, but similar functionality to the 15C), but my everyday work calculator is the same as Chad’s, a TI-30XA, and for the same reasons.

15. Paul Schofield says:

My phone (a battered old Treo) has a calculator about as good as the windows one, which works for most things. It being a smart phone, I used to have a version of Excel on it I could fire up for anything more demanding. However, working Excel on a tiny screen was an absolute pain, and it lacked several vital features (fill, etc) so I abandoned it about two years ago. Might have to see if there is anything better now – I downloaded an advanced calculator for it but never got around to installing it.

16. SpotWeld says:

I’ve a TI-81 that I got back in high school that is not in residence at my desk at work. And a slightly more tricked out TI-89 that I got in college for variable calculus. (It’s such a lovely differnetial solver too…)

17. Frank says:

I also usually screw up all but the simplest calculations when I use non-RPN calcs, but I pretty much use anything within arm’s reach. I’ve never used a graphing calc for graphs, though I own an HP-48GX that was given out at work. You’ll find pretty much everything from 4-banger calcs on up strewn about my lab.

I used to collect HP calcs, or rather, if some idiot was tossing an HP35 red dot cause they didn’t know just how rare they are, I’d take it. Same in the case of the moron who tossed the HP15C that had never been opened. One of these days I’ll make my millions on ebay with it.

18. breton says:

The calculator I use most is my cell phone, since it’s what’s in my pocket when I need to do something more complex than I can handle in my head. When I’m teaching psych stats I recommend the Casio fx-115 and the TI 30XIIs since they are solar/battery powered, can handle two-variable statistics, and are much less expensive than a TI-83 or similar. That means I own, and can actually use/explain all the stats functions of both. For “real” math, I tend to do stuff with Matlab and R (and SPSS if I have to use it).

19. CRM-114 says:

TI-36 and Casio fx-115D. Since I can’t see in the dark, my calculators are solar powered.

If I need something more powerful, I can write functions in scripting languages.

20. Chasmanian Devil says:

HP 42 and HP 33s – RPN is what I started with so TI never worked for me…

21. I still use my old Casio fx-3900P. I like that I can see the formulas i type in (but the display is only 14 characters), and I’m used to it so I don’t have to think about how to find the right buttons.

22. I have a TI-89T, but that sits at home in a drawer — at least I think it is still there.

But I carry the updated version of yours: a T-30XIIs. When dealing with students, I rarely need anything more.

23. As I type this, I have in my pocket an 8-digit solar and battery powered “Base10 SR50” 4-banger that I got free years ago for opening a checking account.

It has +, -, /, x, %, and square root. That’s all. I carry it with me when I’m going someplace with no computers, and I use it to do anything that I can do faster than with paper and pen (which I also often use for Math and Science).

When I taught Math in university, there were specific graphics programmable calculators required for the classes. Most students bought their own, but I had a box of them (with serial numbers scribed onto the case) for students who forgot to bring theirs to an exam. Don’t remember the model, but they were way cooler than anything I’d owned.

But I do usually use Google’s calculator, or Mathematica (when I’m on a Caltech PC that has it installed), or Python on my old malware-damaged PC. Or, for that matter, special purpose online calculators such as the Alpertron for factoring and prime testing, or the great resources of the University of Nice’s
WWW Interactive Multipurpose Server with:
# Lessons and references on various topics.
# Online calculators and plotters : numbers, functions, matrices, curves, surfaces, etc.
# Interactive exercises of various styles and levels.
# Mathematical recreations : puzzles and games.
# Virtual classes and portals to manage scored student works.
# Misc. interactive documents.

Anything involving sequences of integers, there’s no competition for the Online Encyclopedia of Integer Sequences, hosted by AT&T Research, with over 133,000 web pages and great search capability. Just google “OEIS” to find it. As of this morning, there are 1,874 integer sequences that I authored or to which I supplied comments. Some of those I computed on paper, some with my 4-banger, some with Python, some with Mathematica, some from journal publications or books or the arXiv, and some with the specialty online calculators listed above. The killer app at OEIS is using it as collaborationware, as every page gives the name, datestamp, and email address of the author(s).

And didn’t we have a thread here once about slide rules? I still love my slide rule. I wish that I could find my slide rule tie clip.

24. Aaron says:

Oops hit enter and backspace at the same time it should have ended:

The calculator is big enough that it has all the features I need to calculate anything with the basic features that are required for long calculations (being able to review what you just punched in and using the “Ans” from the previous expression), but small enough that it fits in a jacket pocket next to my wallet.

25. John Novak says:

An HP-48 something or other graphing calculator.

More than anything else, I use it for the stack, the reverse polish notation, and the graphing window that’s big enough to display four lines of data. And the interface that is so familiar I can use it blindfolded and lefthanded.

I do occasionally use it to set up a numeric intergation or solve a system of equations, but that’s primarily because I don’t have MathCad or Mathematica installed on my desktop PC and it’s easier to use the calculator than to do it in Matlab or Excel. I figure I do that maybe once a year.

I cannot for the life of me remember the last time I graphed something with it. Probably in grad school.

perl -e
ipython

whatever is closest

I spend my whole waking life in front of computers, why I would bother with a calculator?

27. Aaron Cass says:

M-x eval-expression

28. For me, it’s a matter of matching the calculator to the job at hand.

When working with my electrical students I almost always use a TI-85 because I can do simultaneous equation solutions with complex coefficients in a snap. I also have a TI-89 which has “replaced” the TI-85/86 (86 is basically a warmed-over 85). This is most unfortunate as the 89 will sometimes freeze when trying to solve the above-mentioned equations if the coefficients are in polar form (gotta use rectangular which is a pain in the butt most of the time). Then you get to take the batteries out to unfreeze it.

I also have a TI-30, mainly because a lot of my students in Science of Sound (science elective for non-majors) have one. For every day use I have a little scientific calc circa 1978 made by APC. It’s a classic thin LCD calculator with tiny buttons and does most of what I need except the matrix stuff. Obviously, it does not do any graphing, but I never use my calculators for graphing. There are better tools out there for that purpose. I used to have a Sharp solar scientific circa 1985 that I really liked, but that was stolen.

One cool thing about the 85 is that you can perform basic math operations in other than base ten. I also like the built-in rounding/significant digits setting and the ability to have it display using engineering notation vs. scientific notation. (The 89 also has these abilities, and setting up the calc for engineering notation and 4 significant digits is the first thing I have my freshman groups do with them.)

29. I still have my old Casio (replacing an infamous TI-55 III) and my unwieldy HP-28C, but for regular work I use a HP-48S I got from a friend. He wasn’t using it and I needed a reliable RPN calculator so it went to me instead of eBay.

I have the worst time using GUI calculators on computers. Usually I’ll drop to a command prompt and use ‘perl -e’ or bc or punt to a spreadsheet if I’m doing something complex.

30. onymous says:

I haven’t used a calculator since my first year of college; I use python for most things, Mathematica if it’s complicated. All those hours of detailed graphing calculator instruction in high school math classes have gone to waste.

31. Moshe says:

Calculator? what for? I thought those went away together with the dedicated word processors, replaced by proper computers.

32. Almost all interesting calculator operations can be done mentally.
At least that has been the case since my old Casio scientific’s battery ran out.

However, for emergencies, Mac OSX as a decent native calculator, with a slim RPN scientific mode for flashbacks to the Good Old Days

For plotting stuff – SM of course.

33. My department provided me with a TI-84+ for my teaching, along with a cool overhead projector display (just a basic LCD screen that sits on the overhead, and displays what’s on my screen). As much as I avoid using my calculator for most things, it’s really handy to be able to produce accurate graphs for my students on the fly (my board-drawn ones are sometimes unconvincing) — “Yes, that line really does look tangent to the curve!”

34. Nathan Williams says:

In high school and college, an HP 32S. Marginally programmable, but not in a way that was ever really useful to me. Writing programs to test the primality of 12-digit numbers during boring classes was about all it got.

These days, when I’m in front of a computer; dc/bc/matlab. When I’m not, or want a more freestanding calculator, RPN on my Palm.

35. Aaron Lemur Mintz says:

Small stuff, pen-and-paper all the way.
Slightly larger stuff that I want to follow my process, python.
Hairy stuff, Maple.

In High school had the TI-83, handy for programming in the cubic/quartic/quintic roots.

University I went with whatever they told us to buy – math degree, so no graphing.

36. Eric Juve says:

I use the HP32S, I agree with many of the posters about RPN, it is the only way to implement a calculator. If I am sitting at my computer I often use an HP16C implemented in Windoze. I have been trying to buy an HP16C on E-Bay but they always go for way more than I am willing to spend for a used calculator, somtimes in excess of \$500.00.

37. Matthew L. says:

I used to use a TI-89, but someone stole it when I was tutoring other students before finals (how’s that for gratitude?).

Now I use whatever is at hand—dc when I’m on a command line, google when I’m on the web, and my cell phone when I’m not near a computer. If it needs programming, I typically use Scheme, which has very handy bignums.

38. Pen and paper; dc/bc; units (for conversions); xcalc (-rpn); bash shell; awk; and sometimes but very rarely, my mobile phone. I have an HP (-15C ? can’t recall now) in a box somewhere, and whilst a good unit, haven’t used it in ages. I think it’s in the same box as my dad’s sliderule (which is around 60 years old now, and which I think I remember how to use, but haven’t for a long long time…). Another Unix tool from the distant past I used to use as a calculator was adb. Plus I’ve written a handful of “calculator” tools over time, usually for specialist purposes (and hence most(? all?) are now long lost and forgotten).

39. Sven DiMilo says:

HP-15C, baby. Got it my first semester of grad school because it did linear regression. Still have it, still use it (though mostly for the checkbook anymore).

40. thistleingrey says:

@Paul #15: you might find Calcul-8 interesting (David Griffiths). I used it on an old Tungsten C, and despite the 2002 date, it runs fine on my Treo 700p. Here’s one of several dl links.

41. Gray Gaffer says:

Showing my age, I started with a Bowman 4 function in the days when the use of calculators in exams was forbidden on the grounds that we would forget how to do arithmetic in our heads, a skill that the exams tested back then. They were right too. But they allowed me to use my Aristo 0968 (which I still have). Few cash register clerks can minimize change any more (e.g., for \$4.05 I give them \$5.05. Floors them every time.)

Then on through the HP RPN path, from HP 25, 35, to 41C (which I also still have). Full system, wrote several games on it, also wrote a Hex mode calculator.

Today, mostly Windows Calc in scientific mode or OSX calculator in programmer+RPN mode for the hex – decimal conversions, or my Casio wristwatch for ad-hoc on the road stuff.

42. Jimmy says:

In the lab I use a TI-89, mainly because I like to define custom functions for frequent-but-tedious calculations. Much more convenient than using an Excel spreadsheet, or other things I’ve seen colleagues use, given that I don’t always work right next to a computer.

On my desk, I have a little solar-powered calculator for simple stuff. And I have a Pickett slide rule I found at a garage sale, which I use on occasion to freak out undergrads. ðŸ™‚

43. Brandon says:

TI-89. Most powerful calculator there is, in terms of mathematical capability. I think it says something that the system hasn’t received any significant upgrades in ten years.

For the really hard stuff I use Mathematica.

And for the really hard stuff I use my brain.

44. Eric Lund says:

Most of the time I do the math in my head, or with pencil and paper. When I need to do something involving trig functions of a nontrivial angle (something other than 0, 30, 45, 60, 90, … degrees), I’ll pull out the HP-22S I’ve had since my undergraduate days. For other special functions, I have Abramowitz and Stegun.

45. I’m almost always in the land of pencil and paper or else in the land of huge statistical analysis packages, but I want to put in a good word for the underappreciated units(1) Unix command line utility. I saw someone mention it upthread, but they seem to think it’s only good for conversions. It’s capable of arbitrary arithmetic – I think it even has exponential and trig functions these days – plus it tells you if you got the units wrong! Saved my bacon repeatedly when I was trying to work out CT and MRI profiles.

46. Mike Bruce says:

In school, I used an HP-48G. Mainly for the RPN and multiple lines of output.

Now I mostly use bc for my caveman-level math needs.

47. For years my workhorse calculator model was a TI-35 (IIRC), several of which were supplied by forgetful students; that contributed to a ~20-year stretch where I didn’t need to purchase a calculator. Nowadays it’s an HP 20S (not RPN, used at work) or a TI-30XA (at home), both of which I was forced to actually purchase.

48. CCPhysicist says:

I’d still be using my Texas Instruments SR-50 if its battery pack had not given up the ghost.
http://www.computermuseumgroningen.nl/calculators/texas/sr50.gif
I bought it for the ungodly sum of \$160 back in 1974, mainly because it was less than half the price of an HP45 and still has everything you need to do a physics problem in a very simple layout.

My calculator of choice is a Sharp EL531 that also has commonly used keys like pi and EE as first functions.

My comment about the 30Xa is “If you are going to have parentheses, get ones that work”. I’d recommend cutting it in half on a band saw to show the kids what is inside.

Someone above mentioned the Casio fx-115. That is an outstanding choice for engineering physics and a common choice of my students. Cheap. Clean interface that includes SI prefix input and output instead of powers of 10. Easy to use in complex mode for AC circuits. Does numerical integrals if needed, so it gives up almost nothing on the high end of TI83 functionality.

Like you, I am always amused that kids own calculators that are smarter than they are. Tell them RTFM. Unlike you, I am concerned when I see kids who can’t solve a quadratic equation without graphing it. Sometimes they can’t solve a linear one. IMHO, that is a bit more severe than not being able to do arithmetic. Try giving them a problem without any numbers in it and see what happens.

Oh, and if you don’t allow detailed formula sheets, you should take a look at the sophisticated hypercard programs available for the TI83 and above.

49. dave says:

I have:
(1) A slide rule, with an instruction manual for if I want to use it for more than multiplication or division
(2) A HP-48; the last two times I used it were to do my tax return in two different years
(3) A Macbook, with dc, Maple, and Grapher

50. Al says:

UofA engineering has a list of four approved calculators, One of which has been discontinued, one of which isn’t available anywhere in canada(go figure) and the other is a TI with those impossible to push buttons. So I use a “Casio FX 115 MS plus”. Its pretty much amazing, It can do numerical calculus, repeated formulae, statistics, solve linear systems and do complex numbers..all it can’t do is graph, and I use matlab for that. Its the staple of all my number crunching engineering classes(as opposed to formula crunching physics classes), I’m helpless without it. Oh, and it loves me, they can program them to do that, you know.

51. peter says:

I use the language/platform R for just about everything these days.

52. Either Google calculator or Mathematica 6, depending on the problem at hand.

53. jeffk says:

I think a TI-89 is about the ultimate graphing calculator, but I use a nifty free Windows Calculator upgrade that will do nested parenthesis and graphing (google windows powertoys calculator) My generation can’t operate calculators that don’t understand parenthesis and order of operations. Mathematica if things get messy.

54. Costanza says:

Believe it or not, I use a slide rule (boy, am I showing my age)…I don’t want to lose the skill. But I keep an HP11C to pick up the slack (RPN rules)

55. In order of preference:

Longhand (when there’s more stuff than I can keep in my head)

Excel (when there’s even more stuff)

Perl

I don’t even own a calculator.

56. If I can be off by a little bit, I use my head. It’s good practice and I’m usually pretty close to right (and I get better the more I do it).

My favorite standalone calculator is my HP-48G that I’ve had for more than ten years now. Unfortunately, my computer is usually close at hand, and when it is I use the Windows XP Power Calculator.

57. I use the calculator on my computer, back in the day when I was taking math, I used a TI-80.

-Jeff

58. Tom says:

TI-89 for analytical and numerical integrals, lists, equation solver, matrix algebra and occasionally graphing. Lists are the fastest way I’ve found to check student titration calculations in gen-chem.

I will admit to using a spreadsheet (OpenOffice 2.4) for most graphing.

59. Pseudonym says:

I seriously use two calculating devices in my work.

1. GHC in interactive mode.

I used a slide rule a couple of months ago, but it wasn’t serious.

60. Josh says:

Maple

61. Dan Hocson says:

HP-15C, had it since high school.

62. Craig says:

After breaking two HP-20S’s in as many years in high school, I picked up a solar TI-36, paying extra for a one-year warranty at Brendles.

That was 1992, and it’s still the only calculator I use. Well, that and the widget on my laptop.

63. agm says:

Do it in my head with simplified approximations (things like g=10m/s^2 and such) to get an order of magnitude. Also, this allows me to beat the students punching numbers in when things are worked out on the board and amaze them at how close an estimate I can get without touching any digital logic.

For the actual number, things are input into a cheapo battered solar-powered machine or google. God I miss my TI. Not the 86, which became marginally less useful when it died on my straight out of undergrad, but the solar-powered “scientific” calculator. That had the best calculator interface I’ve ever seen.

Jobs more complex than that, IDL or Matlab.

Pre-fix, in-fix, post-fix, who cares? It’s all operators being applied to operands…

64. Ben says:

I prefer RPN calculators now, but will use either, which makes me some kind of prevert. I have a computer, but for quick calculations it is easier to enter numbers on the calculator.

For everybody who wonders why fancy programmable calculators exist: I dunno, but way back when, my dad bought a TI-57 programmable to teach me how to program. This was before home computers dropped below the \$1000-2000 mark (a ton of money at the time). The TI-57 was the most affordable calculator that had a branching instruction, which is why he chose it, because a programmable calculator without a branching instruction is just a formula memorizer. I still have this TI-57 (TI replaced the keypad for free, years after the warranty expired) and although the battery pack is long dead, it still works on the AC adapter.

The scary thing is that although this story shows that I am a complete fossil, I’m not really that old.

65. I use ROOT‘s inline calculator, because I already have ROOT installed on my computer for other purposes, and I’m usually at my computer anyway when I need a calculator.

66. Ambitwistor says:

When not in a lab, bc or Mathematica, like Aaron. (Sometimes Google.)

When in a lab, it was an HP-49G (which had drawbacks over my trusty but lost HP-48GX), until it got stolen by a student.

67. Clark says:

Though I own multiple fancier calculators, on my desk at work sits my Casio fx-82A. I picked it up as surplus from my chemistry teacher back in about 1998. It was made sometime back in the 80’s and sports an on/off switch. (Not a button, a switch.)

68. cookingwithsolvents says:

I use google for a lot of simple stuff.

When calculating reagents I use a TI-85 that dates from high school (my TI-89 is sitting in a drawer somewhere just because the batteries died first on it when i started grad school and that settled the dueling calculator debate by default). I use the “reentry” button a ton so that I can just add on more dimensional analysis for repetitive calc’s for various reagents in a given experiment. I use Molecular weight calculator with lots of custom abbreviations to get molecular weights. I got it here (according to the “about” screen): http://www.alchemistmatt.com/

69. I want to put in a good word for the underappreciated units(1) Unix command line utility. I saw someone mention it upthread, but they seem to think it’s only good for conversions.

That “someone” was me. I am aware that `units’ can be used for more than conversions. But the question was “what calculator(s) do you use?” not “what can your calculator(s) do?”. I (mostly) only use `units’ for conversions.

And I forgot one specialist calculator tool: factor(1).

70. I still have my Casio FX-7500G, which is a folding version of the FX-7500, the first graphing calculator anyone made.

The graphing function actually died a long time ago, and I usually use matlab or whatever for that sort of thing these days, but when I took stats for my master’s degree a few years back I had to go out and get the Casio new batteries because I really really missed the ability to enter an entire equation and then hit the up arrow and go back and change just one thing without typing it all again…

For quick, simple calculations, I still use another little solar calculator I got in grade school. Solar calculators are one of the most useful things.

71. Most always the awesome Karce Kc-119. Definitely my favourite. Every once in a while on a test the TI-34 II Explorer Plus

72. Sherri says:

I still use the HP-11C I bought as a sophomore in college. I had used some TI calculators prior to that, but they were pieces of crap and broke within a year or so. The HP-11C still works as well as the day I bought it. My now 13 year old daughter uses it as well; she likes RPN better, too.

73. Nicole says:

I have a TI-83 Plus that I was required to buy for a statistics class. It was a waste of money, but not as much so, for me, as a laptop computer. The bigger screen than my other calculator is kind of nice, but I don’t know how to use most of the options it gives me and it seems to go through batteries quickly.

My other calculator, which I mainly use when I’m helping my dad with a construction problem, is a Sharp EL-531L. I know what most of the keys do.

I’m a math student, though, so I most often use pencil and paper. Sometimes I try Maple if I’m feeling brave.

74. Bob S says:

I have used the old trustworthy Casio Fx-260 for many many years, and I still use it. It is the only truly scientific calculator that easily fits in my dress shirt pocket. Any other scientific calculator makes me look like a nerd (which I am).