Jan Łukasiewicz, a Polish logician invented it. He said that he came up with the idea of a parenthesis-free notation in 1924. It's PostFix: Last In First Out (such as 2 3 +), which is the reverse of the usual PreFix (+ 2 3). There is also InFix (2 + 3).
So, it was a notation in reverse by a Polish design. Reverse Polish Notation: RPN.

It shows all intermediate results and has such a simple mechanism. If you can perform the operation,(SIN 30 or 2 3 +), do it. Otherwise, press ENTER and continue (2 ENTER 3+).

I know where my slide-rule is kept, I keep it for sentiment.
I have, and still use, an HP of that generation. The charger and battery pack are long gone so I use 2 x AA.
That RPN is brilliant, did HP invent it?

Nostalgia, the days when HP produced first class electronic instruments and devices
instead of putting out wokist propaganda.

I think I have an HP calculator somewhere in my old memory stash...along with all my drafting stuff including a desk with horizontal and vertical bars.

I spent, on and off, 20 years in printing as a stripper, (creating templates for each job and assembling all the negatives for plating). I retired from printing (but not from working) as VP of a medium size shop.

"Now I see," said the blind man, as he picked up a hammer and saw.

For the Too Much Info collection:.
I've known how to use an abacus since I was a pre-teen. Basically, it's complements of 10 per rod and complements of 5 for above the beam.
I still have my abacus and my slide rule, which includes Pythagorean scales (P, P', Q) that are more nearly precise for larger angles than the common S scale.
And my HP-15C calculator. The HP's have/had perfect tactile button-click. And the essential RPN (to Hell with algebraic notation), which I still use on my cellphone and desk-side computer software.

The Band at the top was....wait....wait for it...................................Abba!

Please explain the meme that I did not understand at all.
It says, "BEFORE CALCULATORS PEOPLE USED AN...
Below are some persons wearing blue (I don't recognize them); below that, the rock group Kiss.
Note: I am not a youngster. I remember when each of the following were new on the radio (just off the top of my head): Flying Purple People Eater, Itsy Bitsy ... Yellow Polka Dot Bikini, Beep Beep (Little Nash Rambler), My Boomerang Won't Come Back, Tan Shoes and Pink Shoelaces..., and Alley Oop.

The home schooling meme would have been better if its creator had used the Harvard comma (also called Oxford comma / serial comma) and proper hyphenation of 12-year-olds. (And “the quarantine” would have been better.) To me it suggests that the person doing the schooling is no better than the (sub)standard schools. The humorous impact is severely dissipated.

That Pinto given to my Dad at 50K miles then to my brother-in-law for another 100K...don't know what happened to it after then.

The car was quick and beat many off the line. I am surprised I never blew it up.

Actually, it would now days....

Bwahahaha, you left out jock strap - or would that be considered a male thong?

Yep, I know what you mean, OUC! In 1975 I traded in my '69 GTX 440 for Pontiac Astra Safari wagon, which is the Pontiac version of a Chevy Vega, because it was a more family oriented vehicle and better on gasoline. Worst car I ever owned and after six months I couldn't wait to get rid of it, but grit my teeth and went on for 30 more payments. Never bought another GM product since.

Here in Michiganistan our Supreme Leader said we have to wear masks when we go to the store, but they can be homemade and non-medical. I'm sure glad I didn't toss out that Lone Ranger costume!

A Quick little story. 1973 Army, Fort Knox, buy a brand new Pinto cause my 1969 Chevy SS impala has been trashed besides the 2 front wheels falling off a couple of times. Leave AIT for a few weeks home, on the way saw a new Vega, rear end collision and burning like no tomorrow.

And they had the Gaul to say that about Pintos when I never saw one on fire...

Loved 'em all again, OUC, but when I got to the flaming Pinto I lost it all, LOL!!!

You could make one...a simple kerchief?
Borrow a Barker from a muslim women?
1/2 a Bra?
A Thong?
A McAfee CD virus program...

Well it could be Nancy's colsnotomy bag -caught wiping her snots on a podium in congress or the Italians on lock down.

I have a doctor appointment in Houston this week, but since I don't have a mask, I guess I won't make it. Masks are mandatory in Houston but not in the county I live in.

OK Carl, I'm not even going to tell you which meme I didn't understand. I'm afraid to. I loved the Trump meme! LMAO.

Interesting thought...if you find a photo like that then send it to me. email: johnson-carl@comcast.net.

I accept all contributor memetributions.

"Bare with us"? Are you planning a meme in which a prominent Democrat politician is caught with his pants down?

Nasty Nancy smears her SNOTS all over the place so she is wearing a ColSNOTomy Bag.
My creation.

Another well done set of memes. Had to laugh out loud at a few. Especially the one of Trump sleep habits.
Too funny, if that is possible.

They spelled "colostomy" bag incorrectly, ruining a good meme. (I have a friend who's daughter has had one since age 4.)

Going to the dogs was wa-a-a-a-a-a-y too relatable...

I am getting very close, myself...the hair on the back of my neck is starting to get bunched up at the shirt collar...

Good accordion caption and me dino loved 2020 the novel and the movie. Also LOL at who sleeps with a supermodel, though I've seen that one before.
Would you believe that a dino would be among 300 million people who could use a haircut~~like right freaking now?!

So do I, that's why I call myself OLD UGLY CARL! LMAO.