Most overrated calculator ever. I only ever used the normal Casio FX something something that I got around circa 2002. 
I swear HP has some type of kickback scheme with Uni’s. They forced us to get either a 10BII or a 12C in first year for our one, tiny subject, we had in the first semester. I got the 10BII because it was the cheapest and only ever used it for that one subject, that one year.
I am not one to judge. If I count my fingers and toes 10 times and get a number between 12-18 more than 6 times I consider that a win 
Haha! When I count my fingers I get 1023. Anything else is just inefficient. I’ve never had to use my toes.
We were actually told NOT to get the expensive calculator. We were told you would not be allowed to use anything except a basic scientific calculator in applied mathematics. For analytical mathematics, we weren’t allowed to use a calculator at all. You had to KNOW that cosine of pi/6 (and sine of pi/3) is sqrt(3)/2, because that came up a lot. All exam papers were always set so that the answer was always a whole number, or a well known constant. If you got something weird with a lot of decimals… you knew you made a mistake.
I was still very very fed-up with the Casio and Sharp calculators of the time, which wouldn’t last a year before some of the digits would go dim, LCD would bleed, or you’d have to smack it to get the batteries to make proper contact. So I bought a 20S anyway. It was barely programmable, and really did help with quickly evaluating polynomials repeatedly, which you needed sometimes to plot the thing by hand. And nobody knew it was (barely) programmable.
I loved that calculator. Then, about ten years ago, I was making a solar panel frame, and I needed to calculate the lengths needed to get the right angle. I needed some Trig, so I fetched my trusted 20S, did the math… and then placed the calculator “out of harms way” on the roof of the car standing next to me.
I am still angry with myself for that stupid move.
Left school having had to use Log Books. 2 years later, hit Uni, to be sent to this class to learn “old people” … how to use a calculator.
What if there is no calculator around I asked, I want my Log Book … go to class!
This was my first calculator. Used 4 x AA batteries, was quite hungry too. I inherited it from my mother:
That was made circa 1973. Which I imagine must be when log books started to fall out of vogue. Or maybe the slide rule had an effect too? I don’t know. I am always fascinated how a mere 20 years have such a large effect, from people using log books to people who have never heard of it.
Edit: I was just reminded of a story my mother used to tell. She has teaching qualification, but some of the subjects were taught at the local university… and there was this professor who would write/move extremely fast, and he would wipe down the blackboard as he needed more space… so you had to be quick. Thankfully, this guy also occasionally used the logbook to calculate even simple things (like two times three), something his students were very thankful for, because it gave them time to catch up!
And today you can get the RPN calls and many HP type calls on yer smartphone today…
RPNGroetnis
Haha yeah, for normal maths calculators weren’t any help. For the technical applications subjects I found the scientific one (never had a programmable one) perfect.
We actually still had to do some of our subjects by looking up rates from tables in a little orange book. No idea why. Probably also just some company that made money by forcing us to purchase the book of tables. I mean, Excel is suitable for any type of complex calculation we’ve ever had to do, and for when you want to put it into production, there there’s specialised software. I found no point in knowing where to find rates in a book of tables…
This is the practical reality, but we would never allow a student to use their smartphone during an exam!
Also, I never felt like becoming familiar with RPN. Maybe I’ll see the point of it one day… But I doubt it. I want to start making sense of a calculation while I’m reading it. Not first get to the end of a sequence of characters before I have any idea of what is going on. Like some languages you also need to listen to a whole sentence, or paragraph, before you can start deriving the meaning. Seems inefficient. I don’t have such a large buffer. 
Same with us - was recommended but I finished my engineering degree and a finance degree later with a cheap casio or sharp or something. Never ever missed an HP and I think it was a waste of money.
German! Well, all Germanic languages tend to slap the verb at the end, so you only really know what is going on when you reach the end of the sentence, but German is famous for this.
Mark Twain used this excellent sentence, which perhaps overdoes it a bit, to show the phenomenon:
Wenn er aber auf der Strasse der in Sammt und Seide gehüllten jetz sehr ungenirt nach
der neusten mode gekleideten Regierungsrätin begegnet…
When he however on the street the in satin and silk clothed very much to the latest fashion government councilor met …
Then in Dutch (as in German), I also love how sometimes you have to look at the verb before you know what is going on. The Pronoun is useless.
Zij lopen naar het park!
vs
Zij loopt naar het park!
In the first case, it is more than one person. In the second case, it is one female person. You know by the form of the verb. Inefficient? Maybe. But it adds some redundancy, which is helpful according to some of my colleagues.
I guess Afrikaans does it in the past tense:
Hy het die bal geskop
But in the present tense:
Hy skop die bal
Guess you just get used to things eventually. But I’m still trying to get used to concord in English. Redundancy… but speaking it means I need to think ahead of what I want to say, determine the correct form of the verb to use, and then speak it, or risk sounding uneducated (which still happens)… Ugh.
After writing my previous post, I did think for a second about how I said “you have to look at the verb before you know what is going on”. Which is actually a terrible truism. The verb does the work… of course that tells you “what is going on”. What is weird to us, is that the verb also tells you something about who is doing the work, that is, it takes some of the weight off the proper noun (Koos) or the pronoun (He).
Afrikaans has largely done away with that. Ek loop, jy loop, ons loop, hulle loop, julle loop, ons almal loop. Na die park. Die winkel. Die hotel. Want alles is ook die, geen gesukkel met geslaglose het-woorde nie!
Makes for a simpler language, but on an analytical level, I can certainly see that some redundancy was lost.
Moving some of the explanatory work to the verb may also be why such languages are less bothered with pronoun preferences. The pronoun is already just a convenient placeholder that does little to no work 
And taking a step back: We got from Karpower to calculators to RPN to language. 
At which point do you derail a detailed thread?
I ended up with a TI-83+ I inherited from an American. It didn’t have a manual so I had to figure out how to do the things I needed for E&E. The best feature was that if you wrote on it in pencil the writing was only visible from a certain angle, which was great for krip notes!
Hewlett Packard was great but made a big mistake getting into PCs IMHO 
