Magic Brain: Last Gasp of the Mechanical Calculator

[@dwmac2010]

My grandmother had one of these back around 1960 when I was a boy. I thought it was amazing. Thanks for explaining how it worked.

[@savage22bolt32]

I remember we had one in the 1960's

[@igorschmidlapp6987]

@@savage22bolt32 I used to play with my Dad's "Magic Brain"...

[@bennri]

@@savage22bolt32 I had one in the mid 1960s.

[@savage22bolt32]

@@bennri you old coot - like me ❤🌞

[@NikolajLepka]

it wasn't until you demonstrated how the carry mechanism works with the hook motion I realised just how clever this device is. Amazing piece of engineering!

[@rev.davemoorman3883]

I remember a bank that gave away a free "pocket calculator" in the 1970 (when electronic calculators were a couple of hundred dollars). It was a slide calculator - and surprised the recipients! Until seeing this video, I assumed the free calculators were wheel-based (and some were, I am sure). Thanks for showing this.

[@dieseldragon6756]

🏦 _„Join us and get a _*_Free_*_ pocket calculator!“_ 😀 ✉ _Customer opens parcel: Sees slide calculator - And a lot of disappointment - Inside._ I assume you're a Barclays customer too, then? 🏦🇬🇧😉

[@_CAT-lg4sr]

As a school boy in the 1960's, I had one of the very device you demonstrated that my parents gave to me as one of my Christmas presents. The trouble was that my second grade teacher absolutely forbade the use of these devices in class! She likened it to a form of cheating and required all work be shown and done in pencil. Oddly enough she taught us how to use an abacus later that year. Not really that much different from one of these marvelous inventions.

[@miscbits6399]

I was going to say that these are a flat implementation of abacus operating principles in a more portable form

[@MattMcIrvin]

@@miscbits6399 The ancient Romans had miniature hand abacuses with sliding beads built into the frame. They could have easily made a Troncet-style adder except that they didn't have a place-value numerical system that would accommodate them.

[@carmadme]

Reminds me at school in the mid 2000s when a teacher said you won't always have a calculator in your pocket We all took out our phones

[@rohnkd4hct260]

My mom used one for groceries shopping. I remember playing with it.

[@marshalt]

How does this channel not have hundreds of thousands of subs???

[@TodayIFoundOut]

He'll get there. Gilles does amazing work. :-)

[@lyranem]

A true hidden gem

[@michaelcherry8952]

I have an Addiator Duplex (addition and subtraction) from the 1950s (I think) that I use on a regular basis. You can perform calculations quite quickly when you get used to it. I also have a couple of miniature (6-inch) pocket slide rules with Addiators built into the back side, made by Faber-Castel. One is a special slide rule for electrical calculations. I'm fascinated by these kinds of devices.

[@wintersbattleofbands1144]

Just a grammar correction. The strips are not corrugated (like a wavy potato chip), they're serrated (like a cutting blade).

[@Mrjcowman]

Over the course of millennia, we evolved from the abacus to this lovely little device: a pocket abacus with extra guides for ease of use. Then in a matter of decades we got electronic calculators that can perform trigonometry in an instant; just a handful of years later, everyone has a pocket function plotter built into their telephones. This really puts into perspective just how revolutionary electronics have been in such a minuscule time!

[@MattMcIrvin]

And if you look inside the processor chip on a microscopic scale, what the machine is doing is essentially abacus operations with electric charge, though in binary rather than decimal.

[@adorp]

But what about the slide rule, and the Curta?

[@johndoyle4723]

Thanks, as an Engineer trained in the 1960s we of course used our "guessing stick", AKA, the slide rule, which I suppose was a simple mechanical device, based on logarithmic scales. When electronic calculators appeared circa 1970 they were very expensive and I was still faster with a slide rule, but of course nowhere near as accurate. I also lived through using hand punched cards/tape and Fortran.

[@JerryEricsson]

The first pocket calculator I got came with a sports coat that I purchased at the JC Penny store in my home town. I needed it for testifying in court as I was a cop at the time and the courts decided we should not appear in uniform because it gave the jury the impression they should always trust a man in uniform. Boy has that changed now days.

[@stevenlitvintchouk3131]

I learned how to program in assembler before I "graduated" to Fortran. But I owned one of these Magic Brain devices too.

[@glennso47]

In the navy in the 1960s I was on a Submarine Tender, a supply ship for submarines,. I worked in a stock room and I was tasked with filling orders from stock. The orders were on punch cards and we were forbidden from folding, spindling or mutilating. Sadly I did that to an order that I filled. I was used as an example a couple days later. 😮

[@ooslum]

I had one of these as a kid in the sixties. They could also be used for simple multiplication and division using the addition and subtraction repeatedly and counting the sequence before being left with the remainder. Good video and memories, thanks.

[@dwm1156]

As someone else mentioned, I had a Magic Brain that had a burgundy plastic back. I bought it around 1966 in a toy store I frequented on weekends whenever my paper route showed a profit… so… not really that often, but I spotted the Magic Brain perched in a rack with a dozen others right by the cash register and knew instantly I must have one, after I had bought the thing I had already saved up for, whatever it was, I’ve forgotten, I did. It came in a flimsy and fairly plain white cardboard sleeve with an even flimsier and faint sheet of instructions to operate what I then considered to be my first computer. I could easily out-calculate it up to four or five digits, even at ten years of age, but it was super-useful for serial addition and subtraction - adding and subtracting columns of numbers like credits and debits. My first computer.

[@billharris6886]

Thank you for doing the history on these ultra simple mechanical adding machines. We had one of those same Magic - Brain Calculators (except in the red plastic body) growing up in the mid 1960's. My dad's career was banking so, a large motorized mechanical adding machine was a regular sight (which made quite the racket when the Total button was pressed). With my interest in math, I was amazed how small and simple these devices were. I did noticed the slides were quite sloppy in movement though but, assumed this was normal. Later, in 1971 I started engineering in high school and the calculating tool of choice was the slide rule. In 1973, the $100 price barrier was broken on 4-function calculators so, within 2 - 3 years scientific calculators obsoleted the slide rules.

[@GeoffRiley]

I remember having one of those operating in pounds, shillings, and pence. It was an ingenious device that was surprisingly quick to use.

[@dieseldragon6756]

Given the difficulty of making modern computers understand £sd: If we do reverse decimalisation - Which would be very on-brand for our present Conservative government - We're probably going to have to order in a *lot* of these things so folk can work out what the bally-'eck a _Shilling_ is! 💷🇬🇧😉

[@incub8]

I have a "Produx Original" with "Made in Germany - West" stamped on the back. It was a gift to me from a very thoughtful friend.

[@refindoazhar1507]

This channel remind me of Technology Connections, from the choice of topic (random everyday stuff of the old days), the way it was presented, the way the room is set up with a bunch of random yet nicely arranged clutters in the background, down to the unusual choice of wearing very formal clothing. Hopefully this channel will be just as successful soon.

[@richardvoogd705]

Wow, a blast from the past! I had one 52 years ago in 1971!

[@CoopyKat]

I had one exactly like the one in this video in the early 70s. I loved it! I blew my mind to see this device again for the first time in decades!

[@ooslum]

It's like being 11 years old again, I bought mine from the back of a comic with one of those "Make yourself a genius advert".

[@CoopyKat]

@@ooslum Same here! I think I was 11 or 12, but I don't remember where I got it from. It's weird to see something again after half a century (for me).

[@mikefochtman7164]

Remember playing around with a 'magic brain' in grade school back in the 60's. A friend had brought it in and we all "ooo"d and "ahhh"d over it. I had long forgotten this until watching your video. Fun walk down an old memory.

[@GatorGirl]

Oh man, I had one of those Magic Brain calculators when I was a kid in the early '70s. I remember I had a lot of fun with this until my parents got me an electronic calculator. I liked playing with that as well, more so than with my dolls. I was a weird kid.

[@TheCatBilbo]

The explanation made my brain ache, but this is such a clever, mechanical device. Never heard of them before but I'm a 80s calculator kid!

[@video99couk]

As a kid I got one of these made of plastic and thin metal, around 1975 when I already had a calculator (which still works). I got quite good at basic calculations with it. Lost it somewhere over the years though.

[@paulabraham2550]

I had a Correntator which was engineered for Imperial weights (oz, lb, cwt etc). Incredibly specific, but in its place, I think, more useful than the simple decimal type. Decimal addition and subtraction are relatively easy to do in your head, but the multiple bases needed for this is a bit brain bending.

[@agranero6]

My father had a Record addiator I played with it without understanding when I was very young. Today I have a Meta, it was a big success when my son brought it to a school fair on a stand of old objects. Incredible how the young got attracted to it and used it without problem the teacher told me.

[@SuperNicktendo]

I was not prepared for that incredible fascinating lesson.

[@ammoalamo6485]

We had one of these in our family in the 1960s. My mother was the bookkeeper for the small family business, and this was her first "calculator", known back then as an "adding machine." Later she got a much improved but still mechanical "adding machine" with levers instead of open slots for the push-stylus that actuated the earliest toy-like machine. Both the cheap one just like this, which at first glance seemed to be a toy, and the newer professional-looking model made by a different company were accurate and durable, so Mom must have been using one of the high quality versions. The newest model was about the size of a large grapefruit, and was much easier to operate due to using self-returning levers instead of a stylus to move the counters. Years later Mom switched to an electric adding machine which printed out the results on a roll of thermal paper, which helped her to double-check her input. But that 'toy' mechanical adding machine stayed in the family for many years, eventually disappearing into the void of some desk drawer, never to be seen again, like the Ancient Mariner's lonely Lost Sock we never could find, either.

[@phyein4815]

When you opened it up I thought this vid was gonna be about a fake calculator toy, and was genuinely taken aback when I realized you were going to show it could actually calculate. This is a pretty cool little device.

[@keyboarderror1]

I've got one of those from my grandfather over 40 years ago. I remember him showing me how to use it but I'd long forgotten. Thanks for reminding me.

[@DaleKingProfile]

We had one of these in a drawer when I was a kid, which I totally forgot about. I don't think we knew how to use it. Thanks for the trip down memory lane

[@EVERSMAN42]

As always fantastic content. I feel lucky the KZbin algorithm got me to the great channel, hope others get lucky as well soon. Deserve so many subs

[@DanielLopez-up6os]

I have a similar one of those, Where you do addittion on one side and flip it to the backside to do Subraction.

[@mikep3226]

I got one of these types of calculators from my father in the mid 60s and used it occasionally until graduating high school in 1973 when he gave me one of the earliest HP35 calculators (he was a TV engineer and through his business connections had a significant discount with HP, as I recall) as a graduation present to take with me to go to MIT.

[@KiwiCatherineJemma]

I had one of these (not necessarily "Magic Brain" branded), back in the early 1970's. I was a kid and our relatives in England used to send us presents in occasional parcels in the mail. Often things not easy to get in New Zealand. I had it for quite awhile but lost track of it decades ago. It came with a little stylus, similar to a piece of broken knitting needle, which I think I used after losing the original stylus that came with it.

[@tfairfield42]

My grandfather gave me a little mechanical calculator. He used it often but it still works well. The brand or model is "Curta" and it looks like a pepper mill 😆great little thing though. Also got an "Addometer" that is quite similar, though much longer, and the use of wheels is much more obvious.

[@WyvernYT]

The Curta calculator is very well remembered among vintage computer nerds. If you ever run into abacus and slide rule fans, they'll happily talk your ear off about it. I hope you take good care of it.

[@Zissou42]

The Curta is far more complicated than this, and by now rare and worth several hundred dollars. Just don't open it up!

[@losthor1zon]

My dad had a couple of these when I was a kid (ca 1970-ish). I never really understood them until now. Thank you!

[@davidgold5961]

Please do a video on the Curta calculator - you will love learning about it.

[@AbbyNormL]

I remember playing with one of these when I was a kid. Didn’t use it much once I started learning how to use a slide rule, which was quickly replace with the wedge shaped Texas Instruments TI-30 calculator. I actually wore to buttons out on a TI-30 while undergoing the Navy’s nuclear power training (lasting almost two years) so I could sit on a submarine and stare at the meters on a reactor plant control panel.

[@w2tty]

I had one of these. It must have been late 60s or early 70s. I forgot all about it. Thanks for the memories!

[@vasilis23456]

It's much easier to understand complements in binary, I never really thought about using them in the decimal system and it's pretty cool.

[@philgiglio7922]

Now, do a Curta calculator. All analog and would add, subtract, multiply, and divide. They were very popular with rally drivers in TSD rallies.

[@dhpbear2]

Wow, this brings back memories. I had one these when I growing up in the 1960s! Thanks! I haven't seen it in something like 55 years!

[@DavidKutzler]

I remember when I first saw one of these. Around 1962, Mr. Johnson, my sixth grade homeroom teacher pulled one out of his pocket to calculate something. I bought my first electronic "pocket" calculator fifty years ago in 1973. It was a basic, four-function calculator that cost $99, which is over $680 in 2023 dollars.

[@InssiAjaton]

My father had one similar calculator, all stamped metal. He used it for our farm book keeping to the end of his life. Although he had a marvelous ability to do the calculations in his head. I inherited some of the in-head math capability, while my brothers did not, or at least not as well as I did. When our father died, one of my two brothers took over the book keeping. By then I had bought myself a second hand rotary calculator for my studies. Even later I gave that manual rotary one to my brother for his book keeping help, as I had just purchased oneHP-35 electronic pocket calculator that did much more than just the 4 basic operations. I needed logarithms and trigonometric functions in my engineering profession. Besides the adder calculator my father had also a business oriented slide rule. I don't know what my brother did eventually to the Brunsviga mechanical calculator. I know he kept it at least some years after we had sold the farm and he did not need it for the farm book keeping any more. The simple adder almost certainly was discarded already before the farm was sold. Such memories, however, still remain in my otherwise overloaded head 😊.

[@budgiefriend]

Thank you for an interesting insight.

[@MarinCipollina]

I had one of these as a child in 1967 or so.. It was stamped metal, very cheap, and looked identical to the one used in this presentation.. I remember that part where when adding numbers, one had to continue the stylus movement to click over to the left, moving that column one number, the 'carry over' function in addition.. Lost to the sands of time, I have no idea what happened to it.

[@kgblankinship]

I had one of these as a kid around 1970. It proved to be very useful for simple arithmetic calculations.

[@svgalene465]

My grandmother gave me one of those when I was a kid back in the 1960s. I’d forgotten all about it until I saw this video.

[@cdlp8131]

My mother had one of those (Rectar brand Addiator) and now I keep it with loving care!

[@pauldogon2578]

I had one of these in 1974, brilliantly simple, no bobberies required

[@ManuelBTC21]

Fascinating. This might have a nice application today in teaching low level software developers about twos-complement arithmetic, since that is still the most common way addition is implemented in hardware.

[@esra_erimez]

You beat me to this comment

[@xlerb2286]

I still have one of those in the desk drawer from when I was a kid. It wasn't really of much use but it did work (I still have the stylus too).

[@joesterling4299]

Same here, except mine is in a box in the garage since last time I moved. It was more of a novelty than a useful item, since it fell on my lap from older family years after pocket calculators were already a thing.

[@davannaleah]

My goodness! I never thought I would ever see one of these again. I bought one off a school friend for $1 when I was 12. Unfortunately it broke after a while and decided to make something that basically worked the same way. I made it out of knitting counters. You know the ones you put on knitting needles to count the number of rows that you knit. What I did was buy 4 of them, they were 2 digits each, and glued them onto a short length of knitting needle. With a bit of practice I could use it to add and subtract up to 8 digits almost as quickly as with your little device.

[@RabRabNZ]

I just found your channel from this video, and holy moly what a gold mine! Could you do the Curta next? Or Nagra SN?

[@CanadianMacGyver]

I actually just acquired a Curta, but I'm going to build up to it by covering over adding machines first. I plan to make it my 100th video :)

[@alext8828]

A late friend of mine was an architect and used one of these all the time. Mostly to make fun of calculators. He could calculate feet and inches faster than with a calculator and was always up for a race. I don't know what particular one he had but it was silver and a stylus or pen was used to move the tracks. Wonderful things.

[@dieseldragon6756]

This is a funny thing actually: Living in a country that prefers Imperial but (Up until a few years ago) was obliged to honour Metric, I've found myself working out and learning the decimal conversion factors between Metric and Imperial, and can now mentally convert and run these through a calculator almost instinctively now. 🇬🇧💱🇪🇺 I guess this is a natural outcome of growing up in an all-Metric world and then suddenly finding your country leaving that trade union which kept it supporting the Metric system for the entirety of your life... 🙃

[@LogicalNiko]

I remember playing with one of these as a kid. My father used to have calipers, slide rules, mechanical calculators and other similar tools from his college days mainly stored in the drawer where we used to keep bills and such. I don’t know how many of those I probably abused pretending they were spaceships or other random things.

[@deltavee2]

Well I've watched a few in quick succession and among many other things I've found it that your work is addictive. Clean, logical and well presented. Glad I subbed an hour ago! Keep it up, Gilles!

[@bgfd1]

I had one of these when I was a kid in the early 1970’s loved it.

[@marklsimonson]

I vividly remember the Chadwick model. We had one in our household and I would play with it as a kid, and I'm pretty sure I learned how to make it work. The world used to be full of mechanical things like this when I was young and electronics hadn't yet taken over. If you can get hold of one, you should do a video about the "Digi-Comp I", a simple mechanical "digital computer" from the early sixties made of plastic, metal rods, rubber bands, and cardboard which you could program with plastic pegs.

[@FlintStryker]

I have one of those. Mine’s red. Got it when I was a kid. Now I need to go play with it. It’s in a drawer at work. Wow!

[@mteifke]

I still have one of these with the original box and instrution, and it still has the original stylus although one of the brackets for storing it is also broken

[@KarldorisLambley]

it is always a good day when i learn a new word, thank you for this- rabdology (uncountable) (arithmetic) The practice of performing arithmetic using Napier's bones.

[@Jack908r]

Oh wow. I'd forgotten all about these. Had one when I was younger. Also, back then I could use a slide rule for basic math as well. Still have the slide rules. And I remember when my dad brought home from work one of the first mass produced desktop calculators. It was huge and had small tube lights for the numbers. Thanks for the memories.

[@joelmoses2599]

I remember seeing one as a kid. Thanks for the explanation!

[@stefanbehrendsen330]

Nice! I have the ARITHMA Addiator on my desk at work. You can still find nice examples of them on ebay for $20-$30, but I found mine at a garage sale.

[@SuperMrHiggins]

I love the term Addiator and am going to use it exclusively from now on.

[@anomonyous]

Making something complex in a remarkably simple form is far more impressive and the mark of a truly intelligent mind than simply making something complex.

[@zeniktorres4320]

Wow this brought back memories. I had same one, used it heaps. I think I still have it. I have one with the calculator and slide rule combined as well.

[@stevecastro1325]

We had a magic brain calculator when I was growing up; I was always fascinated by its simplicity of operation.

[@hoofhearted3567]

I’ve got one - in perfect condition and works great. Even has the original instructions !👍

[@postal_the_clown]

Mine came as an Xmas gift in '63 from the Sunset House at the South Bay Center in Torrance. 'Nuff said for those who remember. Stayed with me 'til the late 80s at least.

[@macsnafu]

I had one of these as a kid in the 1970s. I bought it through a comic book ad. I lost it at some point, but recently found another one at an estate sale. The original one I had was exactly like the model shown in the video, but the one I have now has a more elegant gold and white design, and just says "CALCULATOR" instead of "MAGIC BRAIN CALCULATOR".

[@jasonrodgers9063]

I used to have one of those "back in da day". Had totally forgotten until I saw this video!

[@fireballxl-5748]

I owned one of these. Thanks for the memories!

[@TaijanDean]

I have an 'Exactus' sliding calculator and it is my favourite portable mechanical calculator. The Comptometer would usually take that category but it is a little on the large size to fit in a pocket 😄

[@jeffreyyoung4104]

In the late 60s, I had one with the box and instructions. I kept it in the glove box of my mothers 63 Ford Mustang. I used it for math homework, but I don't remember how to divide with it. I lost the original, but I recently bought another one!

[@inregionecaecorum]

I had something very similar but even more compact. In fact I still have it, it cost me six shillings and sixpence back in the day. I graduated onto a slide rule in high school and then one of the first texas instrument calculators.

[@chap666ish]

I got one of these in 1975 or '76, in fact I used it at school a few times. In fact I might still have it somewhere in a box in the loft.

[@argusfleibeit1165]

One of those showed up at our house, sometime in the 1960s. I think it came from a neighbor who moved away after his wife died. I don't remember any brand name on it, and nobody really used it-- my dad had a mechanical adding machine that he used for his insurance job. I used to fiddle with the "magic brain" one. I don't know when it disappeared from our house. It was kind of fun to play with.

[@Dilbert-o5k]

I fell into the gap where slide rules usage were no longer being taught and electronic calculators were still not cheap enough for general use. The first i saw was an early adopter who had one of sinclairs strange calculators with its reverse polish notation. We did do a couple of sessions on the mechanical rotary adding machine in primary school, to prepare us for the future😊

[@wisteela]

Very interesting device. I will be checking out the other simple one video too. I'm wondering how you do multiplication and division on it.

[@adamb89]

I used to have one of those as a kid in the 80's. I preferred using it to a regular calculator, since the fact that it was entirely mechanical made it seem cool and unusual.

[@poubelle_blanche]

I have one of these, it is awesome. This and some Napier bones taught me math.

[@philiptownsend4026]

I had one of these, or something very similar,when I was a kid in the early sixties. I had completely forgotten it. It was fun and fitted in my shirt pocket. I think my parents saw it as an educational aid ;-)

[@jdwilliams518]

i have one similar that i found at a rumage sale in the 80s as a kid.. i got pretty good .. think i still have it...

[@mikeyoung9810]

I had something like this (not sure as I had completely forgotten this) but can't quite remember what it looked like. (this was back in the 60's).

[@philcoogan7369]

My father had something quite similar, but made all in metal and green and gold in colour. Oh and it worked in British pre-decimal currency 12 pennies to the shilling, 20 shillings to the pound. Can't remember if it coped with ha'pennies and/or farthings (2 ha'pennies to the penny, 2 farthings to the ha'penny)

[@philcoogan7369]

PS it was a lot smaller than the one you have hear as I recall

[@richlaue]

My father had a mechanical calculator (bought by Bell Labs) that was motorized It had 3 sets of pushbuttons to replace these slides. You could do, addition, subtraction, multiplecation, division and powers. Some problems might take 10+ minutes to calculate, making for some interesting beats.

[@MrLamchp]

I saw the thumbnail and realized that I had one as a child. Never figured out how to use it until now.

[@dadw7og116]

Cool. My dad had one of these when I was a kid. I remember taking it to school when I was in grade school.

[@Tech-Relief]

I had one of those as a child, forgot about it until i saw it here. Must be getting old 🙂

[@paulbalogh4582]

Wow - I remember, wish I still had mine plus the original Rockwell calculators… Big green numbers & little rubber feet..

[@davidkohler7454]

I still have the one my Grandfather used when I was a youngster. But it is made of green painted metal with a row of rotary dials like a telephone and a row of square box windows at the top that displays the numerals that are entered with the dials. I used to love playing with it back in the 70,s .My Grandfather is probably the reason I have always been fascinated with maths.

[@danmartens8855]

I had this when I was a kid! I totally forgot about this.

[@kensmith5694]

Did you know that there is a way to compute a sqrt() on one of these although it is easier if you have two of them to work with. The method works from 2 facts: 1) The sum of the first N odd numbers is N^2 eg: 1+3+5 = 9 2) If you multiply a number by 10 its square goes up by 100. Basically you need to keep track of the next odd number to subtract and what remains after the subtraction. To do this with just one calculator, you use the left sliders for the remains and the right one for the "N". The odd number is (2N-1)

[@colinbuck8687]

“That cheapness came at a cost.” Love it.

[@MattMcIrvin]

Complements are being used a bit differently in the Magic-Brain than they are in, say, a Comptometer. If you look closely at one of those, the complementary digits provided for subtraction are nines' complements: every subtraction digit is 9 minus the regular digit. Here, they're tens' complements. The reason is that the Comptometer has an automatic carry mechanism that always operates in addition mode. To subtract, you add the 10^n complement of the *entire multi-digit number* according to the formula in your video. As it happens, that's the nines' complement of every individual digit, except that you add 1 at the end. And, as you said, you have to suppress, undo or ignore the final carry. Here, subtraction is done with the tens' complement of every individual digit. That works because the Magic-Brain can just have you do the carry differently. And it means there's no special funny business with having to add 1 or ignore the final carry. Much easier to explain.

[@NoahSpurrier]

I’ve got a few of these. They are pretty cool.

[@mekkler]

I have one of the Wizard calculators. One of the tabs is broken off. I still have the original stylus, the vinyl case and instructions.

[@jamescorvett]

I have several different types of these old devices. I think mine were from the 50-60s but Ive not looked them up online. Never knew the history of them, thanks for the history lesson! Edit- I think my mom used them for crocheting or knitting large items

[@michaelmoorrees3585]

I had one of these, as a kid, in the 1960s. It broke, and was tossed, in less than a year. Didn't appreciate complements until the 1980s, when using them in digital electronics classes, in college. Some early microprocessors didn't have a subtract instruction, but used 1's complement (inverting), but by adding one, gave you 2's complement, which would give the equivalent of subtraction. My first electronic calculator was a TI SR11 (LED), which cost me ~$30, in 1975. It was replaced by a cheap Sharp scientific (LCD) calculator, during college, for ~$20, which had many more functions. I think both could display numbers in scientific notation. Important, if you're taking engineering classes. I think the Bomar Brain cost ~$400, in the early 1970s, which was the first electronic calculator aimed at the consumer market. You could buy a working used car for that money, back then.

[@sherwoodbrooks8163]

I think the intro music is from “Danse Macabre” but what is the brass music used on his other channel? The Cohen’s used that piece in “Burn After Reading”. Anybody? Anybody? Bueller?