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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...