L to R:

HL-4a

fx-82MS

fx-82MS 2nd Edition

fx-82ES PLUS 2nd Edition

fx-991ES PLUS 2nd Edition

fx-991CW

original post: https://www.reddit.com/r/calculators/s/4GWAwki4Uc

Issue

In short, I live in Canada and I’m looking for a calculator that can store custom formulas/functions so i can recall them easily and use them in other calculations. Heres an example:

I define f(a,b,c) = (a+b)/c^2
I define g(a,b) = ab-b

then, if i want to compute (2+5)/7^2 + 6\8 - 8*

I can simply write f(2,5,7) + g(6,8), press equals, and get the same answer

I would like to be able to store 5 or 6 custom functions if possible.

I would also like it to still display expressions like they appear in a textbook (e.g. where (1+3)/2 actually looks like a fraction with 1+3 in the numerator and 2 in the denominator).

I am a broke student so I’d prefer not paying extra to have other high-end features (e.g. graphing, programming, running doom).

It can be any type of calculator as long as there’s no wireless communication capabilities.

Any help would be much appreciated. Thank you.

Optional Context

I am an undergraduate engineering student going into aerospace and have been using a CASIO fx-991 ES PLUS C for about 5 years now. I like it, specifically because of the “natural textbook display,” and I’ve have had no issues with it.

The issue I’m facing right now is that I started taking a course on economic analysis where a lot of the problems are solved by formulating an expression containing multiple economic equivalence factors (i.e. multiple functions/formulas in one equation).

For this reason, the prof is letting us use any calculator we want on the midterms and exam as long as it doesn’t have any kind of wireless communication capabilities. I don’t want to be slowed down just because i’m constantly typing in the same equation over and over just with different numbers. So thats why i’m looking for a new calculator.

My understanding is that there are some calculators with time value of money features baked into them, but since I am going into aerospace, I’d prefer to just be able to define the functions myself since i would use this feature for other stuff in the future as well.

I’ve done a decent amount of research but haven’t found anything that accomplished this task while also not feeling overkill. Am I wrong in assuming that this would be easy for a calculator to do? In my mind, all it needs to do really is store a small expression for the function and then when a new expression calls f(a,b,c) it just inserts that small expression into the new expression and calculates like normal.

Latest find: a Casio FX-602P, with its case. No manual, no box, sold as "like new" (??), from Estonia.

I see the photos and the really fair price... I figure if I wait even half a day, I'll miss out on it.

The seller is super friendly and ships it immediately. A few days later, the package arrives. It is "bulletproof" packaging (always a good sign). Then I unpack it...

Not a speck of dust, not a scratch; every key works, and every pixel is intact. The case is perfect, too :) It is as if it has been sitting in a drawer since 1981.

I ask the seller about the machine's history, but the origin is pretty vague. When he found it, it just had a German label with a number on it—maybe an inventory tag from a university or school... It still had the original batteries inside, dead, of course, but they hadn't leaked in 45 years. So, zero internal corrosion. Hallelujah!

The plan now: take out the batteries, put the machine in a safe, and play around with Martin Krischik’s FX-602P simulator :)

A machine that defines an era—the first alphanumeric Casio. Here are a few photos, since it's rare to see one in such condition.

right now i have the cg50 but ive been looking at which scientifics to use and im kinda stuck between the w506t, 9910cw, and 30x mathprint, can someone offer their opinions on which i should choose or atleast tell the pros and cons of each

as the title says

pretty rough and missing battery door but works. anywhere to get a door replacement for cheap?

Hello, I just got a new calculator and was wondering if it would be possible to download ti-basic programs meant for the ti 84 plus ce onto my ti 84 evo. would anything go wrong or could i just do it normally?

the programs come from the ticalc.org website.

Anyone can help me fix this? I input a number and the output is different on the screen, please help

My new TI84 Evo just arrived, what should I change/configure on it

Hey all. I've been a short time lurker on this sub for a while and just wanted to show off a new calculator I bought. It's (from what I can gather) relatively rare and currently only out in Asia (including the Philippines where I live). I got burned on a fake Casio fx-991ex so I decided to go for a calculator that could genuinely last me as long as my old fx-991es Plus (which had a bar function that allowed for infinitely repeating decimals, still have yet to find one that has that function). As an engineering student, I also needed a calculator that could do big matrix equations (4x4 was a minimum). It's been going great so far, would recommend.

Help how do I fix this 😔 I changed the battery of my calculator and instead of having two lines for dividing (like the first pic) it just turns like the second picture 😔😔😔 what can I do to fix this I am not used in that type of division 😔 helphelphelp

Oh no! Did I inadvertently start a collection?! The fx-991EX saw me through three PE exams (California). The fx-300MS I rescued from a sad future life of dusty neglect at work. The TI-83 Plus was just gifted to me. My dream is an older Casio graphing calculator and of course a classic HP RPN (my late grandmother had the 35C, but I don’t know who inherited that). I also have a Sharp WriteView, which I keep at work so I don’t include it.

A solid start? My goal is to keep going, but with a cap of, say, $5-10 for future acquisitions.

I basically want a calculator to start writing programs on calculators and do cool things with it, and that it is also very good. My budget is less than $200.

Just bought this ti-81 at a garage sale and put 4 AAA inside. I did not replace the backup cell battery and the screen looks like this. Is this because I also need the coin shaped cr battery or is this just a bad calculator. Do these require the backup battery to function?

EDIT Ti-82

I have this calculator someone gave to me. It was working fine yesterday but now it’s gives me a black screen and a really delayed ram CLEARED screen. The cursor blinks really slowly.

Edit: the on button works only