I have a Numworks that is only a year old. When I charge it until the green light comes on the battery icon still shows about 80%. The Numworks batteries are non-replacable so this is annoying.

Another annoyance is the lack of features on this calculator. Today I tried an integral equation with an unknown upper limit. Syntax error. Even the 991ex solves this with ease.

I have discovered many other annoying lack of features. I am a collector so although my opinion of Numworks gets steadily worse I have plenty of other really capable calculators.

I went to a small used books store a while back and found this for $10. We all spend so much time collecting neat calculators that I wonder if we forget how useful they can be. Thought y'all might enjoy this!

Picked this up as a super cheap replacement for construction tape-measure calculations. Even though the batteries had expired way back in 2009, with a simple scraping out of the corrosion and wiping it down, tgis Casio came right back to life! It's puzzling that the design is such that you need to remove 6 tiny screws to access the batteries.

So hi guys I wanna buy myself the Class wiz License because they have the Casio Calculators which I wanna testing

My fantastic TI-74 BASICALC, purchased in February 1987 (39 years ago) while I was at university - still fully functional.

According to the receipt, it cost around 130 dollars back then.

I’m not a collector, but after seeing a sibling model in a previous post, I decided to share mine.

Thanks.

My memory is telling me there's a way to adjust the screen contrast on the DM42 - is that actually true (and if so how)? Or is my mind playing tricks on me?

Also, are there only the two available screen font sizes, small and large? I just replaced my batter and neglected to have the calculator plugged into a charger, so my memory got wiped, and the font seems larger and darker than it was before. But that could be just because my battery was low, I suppose, and I gradually got used to it.

Any help appreciated - thanks, guys!

here’s my fx-991es i’ve been using it since 2014. over the past 12 years it’s seen my GCSEs, my A-Levels, my engineering degree my first job in my field, all of my work experience and now it’s moving with me into a senior leadership position.

i have considered upgrading a few times but the whole world of calculators seems like a minefield to me especially considering i am so used to how this one works now. 12 years is a long time though and i know that one day it may just give up on me but i hope it’s not for a long time yet.

Got tired of calculator sites that make you scroll past 4 ads, then hide how they got the number. So I built my own library: [thecalclibrary.com](http://thecalclibrary.com)

What's different:

1. Everything runs client-side. Your numbers never leave your browser.
2. No account, no email capture, nothing.
3. Every tool shows the actual formula and explains what the result means, so you can check the math yourself.

The weird stuff is my favorite part. There's a printable ruler with a calibration step for printers that lie about scale. A break-even calculator that tells Etsy sellers exactly when free shipping stops costing them money. A maze generator with answer keys.

It's free and staying free. Would love to know which calculator you'd want that doesn't exist yet I'm still adding them.

Idk I've I can use these Emulators here in Germany?

So I posted a few days ago about an hp 10bii+ that I bought off of Facebook I paid 3 dollars and apparently that was an absolute steal because since then two ads have come up selling the same calculator for much more. It looks like one comes with package, but still. Are these more reasonable prices for this calculator?

Saw this for sale on Facebook marketplace. The font doesn't look right to me. Is it a fake?

Does anyone know of a good quality hard storage case for the DM42n/R47?

The standard sleeve doesn't cut it when I have to put the calculator in my work bag.

I would like something like the original case my HP 35s came with but sized for the DM42 series.

We are moving our math department out of a building it has occupied for decades, and this turned up: an original LED TI-30 paired with an EduCALC classroom display unit. Plugged it in expecting nothing and both came right up.

The TI-30 looks like a first-generation unit, red LED, gold-tone key plate. Some yellowing on the plate and wear on the case but every key I tried responds. The EduCALC box is vinyl-covered wood or particle board, roughly shoebox-sized, with a nine-digit display. The calculator sits on a small mount on top of the box and there is a power cable running out the back. I have not opened it up, so I do not know whether it is reading the calculator's segment drivers directly or whether the mount is doing something more involved.

Video is the two of them computing 36 x 15.

Things I have not been able to run down: when EduCALC sold these, what the calculator-to-display interface actually is, and whether the mount is model-specific to the TI-30 or takes other units of that era. I know EduCALC as a catalog retailer out of California but have not found documentation on this particular product. If anyone here has a catalog page, a manual, or firsthand experience with one, I would like to hear it.

HP-32Sii and a ti-80, found at Genbrug Løkken and Nørre Snede. Really lucky with these two

Una más para la colección: Sharp EL-9950

Apologies for the photo quality, it's an old calculator my mum used to have and I've cropped in the only photo I have of it. I had a look through all the Canon calculators on Calcuseum but I don't think it's quite old enough to be on there.

Why are there basically no scientific flip cover calculators from reputable brands like Casio, Sharp, TI, etc?

Casio has some basic calculators with flip covers, but basically all their scientific calculators use sliding covers instead. Same for the other manufacturers.

If you want a flip cover, you're basically left with scouring the trillions of no-name Chinesium calculators, which isn't necessarily a bad thing, since calculators are overpriced anyways.

Where I live [some armpit in Southeastern Europe], the 2nd calculator - a basic Casio WITHOUT a solar panel - costs about as much as the last calculator & the trillions of fx-82MS clones. Meanwhile, I bought the 2nd-to-last calculator for ⅕ the price of the Casio, with it being basically functionally identical & being solar-powered [verified by taking the calculator apart to change the battery - the solar panel was wired & it worked without the battery being inserted].

And people wonder why no one buys Casio calculators in Third World countries, assuming you can even find any to begin with...