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Mechanical calculator with cover removed.
Fullsize image: https://diqn32j8nouaz.cloudfront.net...y_fullsize.jpg
https://diqn32j8nouaz.cloudfront.net...or_cutaway.jpg
Previously:
https://www.homemadetools.net/forum/...239#post165561
https://www.homemadetools.net/forum/...810#post202218
https://www.homemadetools.net/forum/...896#post108875
https://www.homemadetools.net/forum/...959#post137591
https://www.homemadetools.net/forum/...6452#post83701
When I was young, maybe 10-12, a friends dad had one like that, if you just press one button, like 1 + 1, and pull the lever it is not a big deal, but if you push ALL of the 9's times ALL of the 9's it was not so easy to pull the that lever. I do not remember how many columns of buttons , maybe 10 or 12. I am thinking is may have been 12... $1,234,567,890.12 but that was a LONG time ago.
I have a Sears electric calculator that looks like it was never used. It was in a basement for >30 years until I got it about 15 years ago. I wanted to open it and see how it works because these things are basically magic to me. The Enigma machine is less confusing.
Neil
Make sure you take LOTS of pictures when you take it apart so you will be able to put it back together!!!! Also shoot video from all angles!!!
For long sequences of 9's, with a bit of math you don't need to pull the handle at all, you can do the problem in your head, e.g...
999 * 999 = (1000 - 1) * (1000 - 1) = 1000² - 2*1000 +1 = 1,000,000 - 2000 +1 = 998,000 + 1 = 998,001
Maybe normal people can, but I can’t. I am absolutely unable to do even that simple bit of arithmetic in my head. I can’t estimate any quantity, make sense of a spreadsheet (this part causes my boss no end of consternation), or follow instructions that skip operations. As you’d expect this held me back in school and even now limits career opportunities. On the other hand I can build or rebuild anything that doesn’t require higher maths.Quote:
Originally Posted by mklotz
Neil
Nobody is born knowing how to use math. Rather than practicing, many folks will convince themselves they lack some fundamental mental element that makes it impossible for them to learn and religiously avoid any thing they encounter that contains the least element of math.Quote:
Originally Posted by sossol
Learning doesn't cease when you graduate. Examine closely every math item you encounter. See if you can identify specifically what you do and do not understand about it. Done consistently, little bits will stick in your mind. Ask for help; don't be embarrassed to do so. On fora like this one there are undoubtedly many people who share your disaffection. There are also people who are willing to share their knowledge - whether it be how to cut threads or how to calculate the change gears needed to do so.
Most people fail to recognize the differences in how people learn. Some educators are the worst in that respect. I cannot even begin to count how many times in my 35 years of teaching this was demonstrated to me. Often, I would sit in a parent teacher conference and listen to other teachers talk about how lazy and disrespectful a student is in their classroom. More often than not, the student would be at the top of my list in regard to creative thinking, hard work, attention to detail, and a willingness to learn new relevant information.Quote:
Originally Posted by sossol
People are different.
PS. Unfortunately too many math teachers, especially in the lower grades, do not really KNOW math well enough to get kids off to a good start.
I was never called lazy by a teacher (family, but not teachers), but my report cards almost always included something like “doesn’t apply himself”. I had a couple teachers in grade school and high school who adapted to their students’ learning behaviors. Those are the classics we “lazy” students did our best work. Sadly I never found any mathematics instructors who could make that make sense, so never made it past geometry level.Quote:
Originally Posted by hemmjo
Neil
There is Dyscalculia that can make math difficult for some people...
Yes, in 3-6% of the population, far fewer than the number of people who claim they can't learn math.Quote:
Originally Posted by IntheGroove
It reminds me of the dyslexia phenomenon...
Learning disabilities, of which dyslexia is one, occur in about 15% of the population but dyslexia is mentioned in most of the excuses for bad spelling and writing.
I may have that, but I don't think so. Mostly it's my particular mixture of the disorders makes it all but impossible to comprehend anything I can't visualize. The odd thing is that I genuinely like mathematics and statistics. I just can't perform them.Quote:
Originally Posted by IntheGroove
Neil
Dyscalculia; hadn't heard of that one. I'm not minimizing it, but the people who are genuinely born with that disorder have to suffer the association with everyone who wasn't, but still claims it. Like celiac disease and the gluten-free trend.
Seems like whatever is currently trending in society gets a turn at being applied to not learning math. We appear to be backing away from race-based excuses, but this gem from a couple of years ago applied that argument to math instruction: Dismantling Racism in Mathematics Instruction.
AI is really hot right now. Keep an eye out for an AI-themed reason for not learning math.
I'm looking for an AI theme to block Ai from being on my browsers. No computer generated. virus they call AI. will ever know more about what I am looking for when I'm doing a search than me.
Truth. What I meant in my earlier reply is that if I had it I wouldn't know, not that I suspect that I might. I don't mix up numbers any more than anyone else, I suspect, unless they're phone numbers. I almost always get them wrong. Odd, but harmless.Quote:
Originally Posted by Jon
It took cognitive testing and behavioral therapy to make the connection between my math deficiency and other idiosyncrasies, like that I can learn to play songs on my bass or guitar by ear, but can't parse music theory. I can learn songs, but can't improvise. Music theory is basically tonal mathematics.
Neil
Funny timing, or invasive data acquisition?
This was in my suggested videos on YouTube today. The guy says that some mechanical calculators work my addition only. He uses small words, but it still went over my head. Very interesting, all the same.
Neil
https://youtu.be/6l3zCWL1y3Q?si=mYs9dY3nYDnKoAel
I remember the huge metal beast calculators in my Dad's company when I was growing up. It was all they had at the time, and they were frequently being sent to the Office Machine Repair place down the street for a "refurb." One day, while I was at a friend's house, his dad, who sold products for a Japanese manufacturer, asked if we wanted to see something brand new and "revolutionary," which turned out to be a fully electronic, desktop calculator about the size of a volume of the Encyclopedia Britannica. He plopped it down, with it's cool Nixie Tube display, and started running through additions, multiplications, and divisions. He would even do a divide by zero, whence it would flash 8's or E's. He went on to explain asymptotic behavior to us 6th graders by asking us what 12 divided by 12 was, then divided by 6, then 4, and 3, 2, 1. He then asked us if we noticed the answers were getting larger and larger? Next he asked what it would be when we divided by zero, which he did, saying it was so large that it is, "infinite." Wow, I'd just gotten a math lesson that made sense! I look back on that event fondly, even though the persons' names have escaped me. As for me, I'd go on to earn my BS and MS in Engineering with a strong emphasis in Electronics and Mathematics. Perhaps that friend's dad that day had lit a fire?
Kudos to the genius who designed all those levers.Quote:
Originally Posted by Altair
I wouldn't doubt if this guy came up with the idea...
Attachment 46273
My dad used to take devices home from work for use to take apart and see how they worked. One time he had a bunch of electric adding machine. At the time I was around 9 or 10, and was more interested in the cool-looking bits and bobs that machines had.Quote:
Originally Posted by Duke_of_URL
Neil
Another way to explain division by zero is to view division as the process of counting how often one can subtract the divisor from the dividend before reaching zero.Quote:
Originally Posted by Duke_of_URL
An example dividing dividend 6 by divisor 2.
start quotient = 0
6 - 2 = 4 quotient = 1
4 - 2 = 2 quotient = 2
2 - 2 = 0 quotient = 3
now do the same thing with a divisor of zero
start quotient = 0
6 - 0 = 6 quotient = 1
6 - 0 = 6 quotient = 2
6 - 0 = 6 quotient = 3
...
As one can see, the quotient will keep growing forever (in math terms, becomes infinite) while the dividend remains unchanged.
