Calculator Community

A gift from my Calculus teacher upon graduation.

Yes manual included. Sadly the 0 (zero) button no longer works, due to battery corrosion... ☹️

This is the calculator that got me through junior high and high school. It even handles fractions, which is what you see on the display there.

355/113 is a very close approximation of PI, accurate to 6 decimal places.

Yes the calculator also has a proper constant for PI, but 355/113 is a pretty nifty trick in it of itself.

355/113 = 3.14159292, at least on this calculator.

This example was manufactured on the 7th week of 1979.

https://www.calculator.org/calculators/Texas_Instruments_TI-30.html

The Curta mechanical calculators were designed by the Austrian engineer Curt Herzstark, with initial designs from the early 1930s – being half-Jewish, he finished the design while being held prisoner at the Buchenwald concentration camp.

Here's some quotes from the wiki article:

While I was imprisoned inside Buchenwald I had, after a few days, told the [people] in the work production scheduling department of my ideas. The head of the department, Mr. Munich said, 'See, Herzstark, I understand you've been working on a new thing, a small calculating machine. Do you know, I can give you a tip. We will allow you to make and draw everything. If it is really worth something, then we will give it to the Führer as a present after we win the war. Then, surely, you will be made an Aryan.' For me, that was the first time I thought to myself, my God, if you do this, you can extend your life. And then and there I started to draw the CURTA, the way I had imagined it. — Curt Herzstark, Oral history interview with Curt Herzstark (1987), pp. 36-37

[…]

The Curta's design is a descendant of Gottfried Leibniz's Stepped Reckoner and Charles Thomas's Arithmometer, accumulating values on cogs, which are added or complemented by a stepped drum mechanism.

Numbers are entered using slides (one slide per digit) on the side of the device. The revolution counter and result counter reside around the shiftable carriage, at the top of the machine. A single turn of the crank adds the input number to the result counter, at any carriage position, and increments the corresponding digit of the revolution counter. Pulling the crank upwards slightly before turning performs a subtraction instead of an addition. Multiplication, division, and other functions require a series of crank and carriage-shifting operations.

My last acquisition has finally arrived. I am very happy

My 71B is telling me "Data Error" whenever I try to use the variable "F" - any ideas?

Calcula is an RPN calculator with 26 stack levels and 26 storage registers. It is not programmable except you get the Pascal source code and you can create new, possibly complex, functions for the calculator.

https://gitlab.com/waspentalive/calcula

I am looking for suggestions for other functions to add and testing for the existing functions. Free. GPL3 License.

This Casio took me through school, and most of uni. Well battle worn, still working. Please dont send me to calculator jail xD.

I've had this guy for about a 18 months and it is one of my favorites. It is slower than the HP Prime and the TI-nspire CX II CAS, but still blows the TI-89 Titanium out of the water as far as speed goes. The huge touchscreen gives it a unique UI that is easier to navigate than the TIs. I've found that this is the best of my collection for linear algebra, and it is the easiest of my CAS calculators to use.

You can see the bits moving around inside when you use it.

So HP calculators have been ... well not frequent. And from the perspective of a casual calculator user HP might as well not exist. If you wanna buy a new useful scientific calculator it's TI or Casio and maybe sharp. However with the recent announcement that there would be a collectors edition re-release of the HP 15c it looks like the new owners of the HP calculator brand do care! Well at least a bit. So what do you think they will do next? Do you believe HP still has a great calculator in them? What would be your dream HP calculator?

Does anybody else find it odd that the HP Prime stashes the vector field plots in the Geometry app instead of the Advanced Graphing app?

My 30+ year-old Casio fx-7700G is the oldest calculator in my collection. It's a little worn, but still works and gets used! It's been a wonderful companion over the years.

Having used a Ti84+ and Casio FX83GT for my secondary education, and borrowing a HP32 from a classmate at university I really like the stack approach and rpn so I caved with a HP35s which mostly did the job but wasn't pocketable and a bit clumsy for me I found a HP32sii and snapped it up becoming my daily driver for a long time. It scratched an itch i didn't know i had, then wanting to expand my programming and plotting I didnt like the look of the 49g and the 50g being out of my budget I found a nice HP48G that sits on my desk for the more complex work where the RPL hits the needs as well as a "quick" plotter. Even managed to bond with the older grumpy engineers over the calculators and rpn. Im sure my collection will continue to grow.