Calculators you've had

[webny99]

Ahem. I knew I had posted about this before in a bandit thread, but I made a zine about a calculator in middle school. It was called "I'm The Operator of My Pocket Calculator", as I recall.

The first calculator I used for actual math was a TI-30X IIS scientific calculator

Same here, and I still have it, although I was allowed to use it at school, fortunately!

[roadman]

My first calculator (in 1976) was a TI-30, which my parents bought for me when I started high school.  Unlike most TI calculators of the era, the TI-30 used a 9 volt battery instead of the nickel cadium battery pack, so the calculator lasted through my junior year in college.  I remember how, if you pushed a certain combinaton of keys, you could turn the calculator on or off without using the on/off button.

Don't recall most of the brands/models of calculators I've had since then.  For the past ten years of so, I've been using a pair of cheap Wexford solar claculators (one's at home, and one's in the office.  Of course, I'm also old enough that I can reliably do simple calculations in my head.  I've also done up "inches to feet" and "millimeters to feet" (from back when plans were in metric units) charts for typical BGS dimensions.

[Roadrunner75]

I also had this as my first calculator for a few years; it apparently came with a workbook but I don't remember it. I think it's the only thing I've ever owned besides a clock radio which had a red LED display.

The Little Professor, courtesy of 3ryon at reddit:

Wow.  I had one of those....

[Scott5114]

Unfortunately, I could only use it on homework, because at the time I was not allowed to have a calculator in school. To do trig problems, I would have to use a printed table that gave the sine, cosine, and tangent values to three decimal places for every degree value from 0 to 90. And then I'd usually have to multiply that into some 2 or 3 digit number...by hand. If a problem involved pi, I'd have to use 3.14. It absolutely sucked. I lost way too many points on tests because of math errors from multiplying 4-digit numbers by 3-digit numbers by hand.

Thanks for reminding me of one of the most infuriating bits of school. Not letting people use calculators never made sense to me. There is no inherent moral benefit to doing arithmetic by hand; all you're doing is introducing more chances for errors to creep into the process and undermine the student's confidence that they're doing it right. The purpose of teaching math is to teach the process; if you don't know the process to getting the right answer, the calculator is a paperweight.

"Well, what if you have to do it without a calculator someday?" the adults would always smugly ask. My last job involved a lot of math, and it was very important to get the right answers, because a hundred thousand dollars a day depended on it, and any errors you had to pay out of your salary. And every employee had two calculators within arm's reach at all times.

[dlsterner]

I remember having a TI that, overall, looked similar to the second one shown in dlsterner's post, although I think it was an accounting calculator and so didn't list the various trig functions seen on the one in the photo there. (It belonged to my dad and I more or less borrowed it and never gave it back after he got a printing calculator for himself.) This was some 35 years ago, so it's understandable why I don't remember the details.

Just a shot in the dark, could it have been a TI-41 by any chance?

[MikeTheActuary]

Most of my calculators have been different generations of the TI-30, including the old original LED model.

I had a Sharp fx-7000G that I used from my junior year of high school through junior semester of college.

For actuarial exams, I also had a BA-II and a BA-35 at different times, and my first few exams (around the time they started allowing calculators to be used on actuarial exams) we had to buy this miserable little TI solar calculator that could add, subtract, multiply, divide, and do exponentials, and frequently fell apart at the least convenient time...a TI-108, perhaps?

Now, I just use R, Excel, the Windows calc app, or Android's calculator app....whichever is most convenient at the time.

[CtrlAltDel]

When I did get into high school math classes that required a graphing calculator, my teacher was a big fan of the Sharp EL-9600c, since she considered TI's syntax interpreter to be lacking (a few demonstrations where reasonable-looking input gave wrong answers hammered home the point).

Just out of idle curiosity, what are some of examples of these wrong answers? I used a TI-82 all throughout high school and college without really noticing anything weird.

Unfortunately, I could only use it on homework, because at the time I was not allowed to have a calculator in school. To do trig problems, I would have to use a printed table that gave the sine, cosine, and tangent values to three decimal places for every degree value from 0 to 90. And then I’d usually have to multiply that into some 2 or 3 digit number...by hand. If a problem involved pi, I’d have to use 3.14. It absolutely sucked. I lost way too many points on tests because of math errors from multiplying 4-digit numbers by 3-digit numbers by hand.

Thanks for reminding me of one of the most infuriating bits of school. Not letting people use calculators never made sense to me. There is no inherent moral benefit to doing arithmetic by hand; all you're doing is introducing more chances for errors to creep into the process and undermine the student's confidence that they're doing it right. The purpose of teaching math is to teach the process; if you don't know the process to getting the right answer, the calculator is a paperweight.

Probably the best reason to do things by hand is to develop the ability to give a quick “sanity check” to your answers. Having that ability can help identify typos and other such errors as you work. Otherwise there’s a tendency to just accept what the calculator shows even when it doesn’t make sense, like getting 58 − 25 = 83 without taking the time to see that the result has to be smaller than the first number you start with.

That said, there is clearly a limit to this, and having to multiply 2- and 3-digit numbers together is almost certainly counterproductive and perhaps even meaningless, even when compared to something in a more symbolic, but uncalculated form, as in 3π/2, which is often equivalent to a rotation of 270 degrees, whereas the decimal equivalent 4.71238 is pretty much just a number.

[1995hoo]

I remember having a TI that, overall, looked similar to the second one shown in dlsterner's post, although I think it was an accounting calculator and so didn't list the various trig functions seen on the one in the photo there. (It belonged to my dad and I more or less borrowed it and never gave it back after he got a printing calculator for himself.) This was some 35 years ago, so it's understandable why I don't remember the details.

Just a shot in the dark, could it have been a TI-41 by any chance?

May have been. That looks familiar.

[hbelkins]

I had a simple TI (maybe a TI-80) when I was in high school. Square root was the only advanced function it had. Later, I got a more advanced TI which looked similar to one posted early in this thread. It may have been a TI-56. Neither were cheap, IIRC.

Of course, now you can get a calculator for $1 at Dollar Tree.

I used to be decent at doing math in my head, or on paper, but calculators ruined it for me.

[formulanone]

When I did get into high school math classes that required a graphing calculator, my teacher was a big fan of the Sharp EL-9600c, since she considered TI's syntax interpreter to be lacking (a few demonstrations where reasonable-looking input gave wrong answers hammered home the point).

Just out of idle curiosity, what are some of examples of these wrong answers? I used a TI-82 all throughout high school and college without really noticing anything weird.

I remember hearing concerns with accuracy down at the level of 8-10 significant digits. Not a big deal for most homework/tests, and estimations...but probably really frustrating for things that require a lot of precision.

I can't recall specific examples, but I remember that a high school math teacher showed us that different calculators had differing values at the 9-10th digit for trig functions and logarithms.

[hotdogPi]

I believe that entering 2/3X (where you have already defined X previously) gives different results on a TI-85 and TI-86. My TI-84 interpreted it as 2/3 * X, not 2 / (3X).

[formulanone]

I also had this as my first calculator for a few years; it apparently came with a workbook but I don't remember it. I think it's the only thing I've ever owned besides a clock radio which had a red LED display.

The Little Professor, courtesy of 3ryon at reddit:

This wasn't a calculator though right?  This was a quiz game.  Did it have a calculator function?

I recall you could just type in 2 + 3, then GO, and it would answer, but my memory is really hazy on that. Maybe I just used the quiz part a lot.

My grandfather had something like this on his desk, and the sounds were great, especially when you hit the Grand Total (GT) button:



I couldn't tell you the exact model, but it was definitely mostly gray with white, yellow, and orange buttons, and used a journal roll for output.

[Scott5114]

When I did get into high school math classes that required a graphing calculator, my teacher was a big fan of the Sharp EL-9600c, since she considered TI's syntax interpreter to be lacking (a few demonstrations where reasonable-looking input gave wrong answers hammered home the point).

Just out of idle curiosity, what are some of examples of these wrong answers? I used a TI-82 all throughout high school and college without really noticing anything weird.

It's pretty optimistic to think I retained anything from that class, which was probably 15 years ago at this point, when the knowledge given in it has never been used for anything other than taking tests in that class.

So with that in mind, I think it had to do with the fraction bar. I remember a key feature of the Sharp was that it had a "real" fraction bar that clearly displayed what was above the line and what was below. That is, the numerator would take up one line, the second line would be the bar, and the third line would be the denominator. I think the TI had an in-line character representing where the fraction bar was, but wouldn't necessarily put everything before it above the bar unless you used parenthesis. So a reasonable-looking input on the TI would result in a wrong answer, because if you put something like 22+7(fraction bar)16+6 it would interpret that as something like 22+(7/(16+6)) instead of the intended (22+7)/(16+6). On the Sharp it would be simple to notice this error because the "22+" would be off to the left of the fraction entirely.

It was something that is probably second nature to a TI user to work around, but the teacher felt like it wasn't worth trying to instill in the students' heads, so we all bought Sharps instead.

Thanks for reminding me of one of the most infuriating bits of school. Not letting people use calculators never made sense to me. There is no inherent moral benefit to doing arithmetic by hand; all you're doing is introducing more chances for errors to creep into the process and undermine the student's confidence that they're doing it right. The purpose of teaching math is to teach the process; if you don't know the process to getting the right answer, the calculator is a paperweight.

Probably the best reason to do things by hand is to develop the ability to give a quick "sanity check"  to your answers. Having that ability can help identify typos and other such errors as you work. Otherwise there's a tendency to just accept what the calculator shows even when it doesn't make sense, like getting 58 − 25 = 83 without taking the time to see that the result has to be smaller than the first number you start with.

This is a nice thought, but for people like me who, under time pressure, tend to get mixed up and think 7+3=11, or 7+8=16, there is no value in adding an "insanity check". Mental math doesn't work for everyone.

I've gotten a little better with years of practice and dealing with making change at work, but I still know better than to trust my mental math without verifying it with a calculator. To guard against typos, I always use a calculator with a history function or paper tape, and give my input a once-over before acting on the result. Graphing calculators are good about this, as they leave exactly what you typed in on the left edge of the screen and then put the result on a new line on the right.

[Scott5114]

My grandfather had something like this on his desk

Oh man, grandpa calculators are the best. I inherited one of these from my great-grandfather.


So this is a manual calculator that only does addition and subtraction. You input numbers by putting the stylus in the slot next to a number and dragging it toward the windows in the center. If the stylus would go in a red painted slot, instead, you drag it away from the windows, so that it goes around that little bend and carries a 1 over to the next place. To clear you pull out the bar at the top and it pulls all the numbers back to zero.

[CtrlAltDel]

This is a nice thought

This comes across as dismissive, but that generally doesn't seem to be your style, so I'm not sure how to take it.

but for people like me who, under time pressure, tend to get mixed up and think 7+3=11, or 7+8=16, there is no value in adding an "insanity check". Mental math doesn't work for everyone.

I would say that in this case, your mental math is close enough to serve as a sanity check, in that the answer you and the calculator come up with broadly coincide. By which I mean that if the calculator gave you 7 + 8 = 56, your inner alarm bells would go off. That said, a sanity check is not a strict accuracy test, like the ones you seem to have developed.

[CtrlAltDel]

When I did get into high school math classes that required a graphing calculator, my teacher was a big fan of the Sharp EL-9600c, since she considered TI's syntax interpreter to be lacking (a few demonstrations where reasonable-looking input gave wrong answers hammered home the point).

Just out of idle curiosity, what are some of examples of these wrong answers? I used a TI-82 all throughout high school and college without really noticing anything weird.

So with that in mind, I think it had to do with the fraction bar.

Say no more. Despite the generally accepted order of operations, in the "math world," division pretty always happens last, because the fraction bar is considered to be a grouping symbol, like parentheses (and the bar that goes over the radicand in root expressions). The TIs and most regular calculators, though, consider division a "regular" operation, which can mess things up. Having access to a fraction bar as you input would avoid having to deal with that difference.

This also affects things like 2/3X, which was mentioned above. The fraction bar, as well as typographical layout, help make clear how that expression is to be evaluated in a way that doesn't happen with your run-of-the-mill calculators. That is,



So, long story short, I can see your teacher's point.

[kphoger]

I've only ever had one calculator–the one I got in eighth grade–and it still works.  So I don't have much to contribute to the conversation.  But I thought some of you might be interested in the video below.  Try it out with your own scientific calculator and see what happens.  Does your calculator render the following?

11⁶÷13   =   a rational multiple of π

[kkt]

I have had a few calculators:

First one was a Rockwell, from the mid 1970s.  Pretty basic, four functions plus percent, one memory.

Next was a HP 33E.  Yes, one of the 'reverse polish' models, for which you enter the numbers first and then the operation you're doing with them.  It's backwards from the way we write them, but once you've used it a bit it's a lot simpler when working with complex expressions.  It was programmable with short steps (50 or 100 steps, I think) and had 10 memories outside the stack of four numbers.  Wonderfully reliable calculator, in fact it still works.  HP made them to last.  The keys had good feedback so you wouldn't double-press without noticing it.

I also got a HP 32S, which is also a great calculator and still works.

It still amazes me that now TI owns the sophisticated calculator market instead of HP.  I guess it has to do with HP dividing itself between the high-end manufacturer of lab and medical instruments, and the low-end manufacturer of cheap computers and printers, and the low-end manufacturer got the calculator business and the HP name, and their reputation went down after a few years of cost-cutting.

I also have a HP 19B-II, with lots of business functions, loan computations, longer programs.  Bought for my ex when she was studying for her real estate license.

And a couple of slide rules and an abacus, just in case.

[bandit957]

A long time ago, I actually designed a very advanced scientific calculator on a sheet of paper. It had a lot of the features scientific calculators have, but it had some that were totally ridiculous. I think it even had a feature to change the color of the display. or maybe add sound.

[bandit957]

I just remembered that a scientific calculator I had in college had a random number generator. I used it as music selection software when I worked for the college radio station.

[kkt]

HP 33 did not have a random number generator, but it did have statistical functions:  you could input a long list of numbers and it would tell you the total, N, the mean, median, and standard deviation.

[bandit957]

A long, long, long time ago, I read about a weird system of numbers that had names like "megiston". The numbers had squares and circles around them. I think I read it in a magazine when I was very young.

I think the calculator I designed may have used these numbers.

[hotdogPi]

A long, long, long time ago, I read about a weird system of numbers that had names like "megiston". The numbers had squares and circles around them. I think I read it in a magazine when I was very young.

I think the calculator I designed may have used these numbers.

Those numbers are unbelievably large.
https://en.wikipedia.org/wiki/Steinhaus—Moser_notation

[SEWIGuy]

A long time ago, I actually designed a very advanced scientific calculator on a sheet of paper.

Oh thats nothing.  I once drew a spaceship. 

[frankenroad]

My grandfather had something like this on his desk

Oh man, grandpa calculators are the best. I inherited one of these from my great-grandfather.


So this is a manual calculator that only does addition and subtraction. You input numbers by putting the stylus in the slot next to a number and dragging it toward the windows in the center. If the stylus would go in a red painted slot, instead, you drag it away from the windows, so that it goes around that little bend and carries a 1 over to the next place. To clear you pull out the bar at the top and it pulls all the numbers back to zero.

I had one of these - I'd forgotten all about it.