Obsolencia is Spanish for obsolescence, but it sounds more like the name of a mystical far-away land where things and ideas that are no longer pertinent or useful are banished to.
In my case, I can think of so many things that I learned in high school and before that have gone the way of the horse and carriage. Time, style and especially technology changed so many things.
1. Centering a line of text using a typewriter.
Even with late stage (ie late 1980's technology) IBM Selectrics, a typist had to do a bit of thinking in order to get a line centered correctly on the page using a typewriter. Many later electrics and probably some manuals had the ability to automatically tab to the center via a designated key, or, you could keep using the TAB key to get to the center of the page. Then you had to count the number of letters, punctuation and blank spaces in the line, divide by 2, and hit the BACKSPACE key that many times. Now you were in position to type out that line. Next line? Same BS! Whew, what a chore!
2. Long division.
I have no fucking clue how to do this anymore. If a calculator is not handy (but seriously, how far away from a calculator are you at anytime these days...your phone, your computer, maybe your watch, they're all over) you can do de facto guesstimate division in your head for most simple tasks by using multiplication and dividing by easy to remember factors like 1/2 or 1/4, then paring down from there as needed. For instance, if I needed to know what 7% of 168 was I do it like this: I know 10% would be 16.8 and 1% would be 1.68 so I need to subtract 3 x 1.68 = 5.04 from 16.8 which would equal 11.76. Let me use a calculator using actual division....11.76 correct. Now yes, I know I could just multiply 168 by .07 but that is easier to fuck up when doing it in your head. At least for me. Plus, if I was really pressed for time, like doing a multiple choice quiz with a time limit, I can guesstimate the sum faster using my method and pick the answer closest to my estimate.
3. BASIC computer language
Admittedly I never really learned this very well in high school. I only had one semester of it and it was during the infancy of personal computers so we, including the teacher, really were virgin to it all. We programmed on Radio Shack TSR-80s for Christ's sake! The thing'd probably burst into flames if your program were over a few hundred lines of code!
4. Penmanship
Remember when this was an actual course taught in school? Talk about obsolete, this now ranks right up there with spelling and grammar. These concepts must still be taught but I don't think too many of our planet's newest generations are trying to master them. If YouTube comments are to be a gauge, almost no one gives a fuck about grammar and spelling anymore (no penmanship on computers, of course), especially (sad to say) Americans. Ugh!
5. The Metric System
Oh yes, it's very much in use throughout the world, except not here in the US. I remember having to learn all sorts of metric measurements and the imperial-to-metrics conversion tables because, according to my instructors, the US was soon to convert to metrics. Well, as you know, that big conversion never happened. What do I know of metrics now? A gram is about the same weight as a raisin. A centimeter is about the width of your fingernail. (A child's or adult's? I don't remember.) And a liter is half of a 2-liter bottle of soda. That's about all. Never ask me how many kilometers it is to anywhere or how many meters high is something or especially not what temperature it is in Celsius. I'm American and I don't fucking know.
In my case, I can think of so many things that I learned in high school and before that have gone the way of the horse and carriage. Time, style and especially technology changed so many things.
1. Centering a line of text using a typewriter.
Even with late stage (ie late 1980's technology) IBM Selectrics, a typist had to do a bit of thinking in order to get a line centered correctly on the page using a typewriter. Many later electrics and probably some manuals had the ability to automatically tab to the center via a designated key, or, you could keep using the TAB key to get to the center of the page. Then you had to count the number of letters, punctuation and blank spaces in the line, divide by 2, and hit the BACKSPACE key that many times. Now you were in position to type out that line. Next line? Same BS! Whew, what a chore!
2. Long division.
I have no fucking clue how to do this anymore. If a calculator is not handy (but seriously, how far away from a calculator are you at anytime these days...your phone, your computer, maybe your watch, they're all over) you can do de facto guesstimate division in your head for most simple tasks by using multiplication and dividing by easy to remember factors like 1/2 or 1/4, then paring down from there as needed. For instance, if I needed to know what 7% of 168 was I do it like this: I know 10% would be 16.8 and 1% would be 1.68 so I need to subtract 3 x 1.68 = 5.04 from 16.8 which would equal 11.76. Let me use a calculator using actual division....11.76 correct. Now yes, I know I could just multiply 168 by .07 but that is easier to fuck up when doing it in your head. At least for me. Plus, if I was really pressed for time, like doing a multiple choice quiz with a time limit, I can guesstimate the sum faster using my method and pick the answer closest to my estimate.
3. BASIC computer language
Admittedly I never really learned this very well in high school. I only had one semester of it and it was during the infancy of personal computers so we, including the teacher, really were virgin to it all. We programmed on Radio Shack TSR-80s for Christ's sake! The thing'd probably burst into flames if your program were over a few hundred lines of code!
4. Penmanship
Remember when this was an actual course taught in school? Talk about obsolete, this now ranks right up there with spelling and grammar. These concepts must still be taught but I don't think too many of our planet's newest generations are trying to master them. If YouTube comments are to be a gauge, almost no one gives a fuck about grammar and spelling anymore (no penmanship on computers, of course), especially (sad to say) Americans. Ugh!
5. The Metric System
Oh yes, it's very much in use throughout the world, except not here in the US. I remember having to learn all sorts of metric measurements and the imperial-to-metrics conversion tables because, according to my instructors, the US was soon to convert to metrics. Well, as you know, that big conversion never happened. What do I know of metrics now? A gram is about the same weight as a raisin. A centimeter is about the width of your fingernail. (A child's or adult's? I don't remember.) And a liter is half of a 2-liter bottle of soda. That's about all. Never ask me how many kilometers it is to anywhere or how many meters high is something or especially not what temperature it is in Celsius. I'm American and I don't fucking know.