I’m afraid I don’t understand the recent focus on Common Core as being responsible for this kind of crap.
Much the same thing was going on in the 60s when I was in grade school. Except then we called it New Math.
Here’s a primer:
https://www.youtube.com/watch?v=UIKGV2cTgqA
Yes, I’m old enough to remember New Math. Remember the Outcome-Based Education that came afterward?
Common Core is the latest means of enforcing mediocrity.
Only eight posts before Tom Lehrer. Excellent work :)
I believe the idea behind the whole process (including Modern Math from the 60s and 70s) goes something like this. Ask people who are really good at math—naturals at it—how they went about discovering math facts. Then try and develop a math curriculum around those ideas and methods. Solving math problems in base 8 seems really neat to the math geniuses, so everyone should learn how to do it. The problem is most people aren’t math naturals and never will be. The rote memorization of times tables isn’t very creative, but it does work—and apparently works much better than these newer more ‘modern’ ideas. But getting the correct answer is not nearly as important in this world view than the style of your attempt at the answer.
You see the same idea in basic science education. Rather than teach what has been already discovered, they try to get the kids to rediscover well-known facts on their own. So we end up with a bunch of science illiterates.
So how did you subtract large numbers before the base-ten system?
I went to school in the 60;s...we learned that 9+6 was 15.
Pretty damn basic...the evil 7’s gave me fits but sheesh...one of the parts of 6 is 5 and a 1??? really??? so are 3’s...and a pair of 3’s along with 3 of a kind 3’s or 9, beats the heck out of 10 and 5 waitin for a straight.
Excerpt of "New Math" with Lehrer teaching the subtraction problem 342-173:
...
"Now remember how we used to do that. three from two is nine; carry the one, and if you're under 35 or went to a private school you say seven from three is six, but if you're over 35 and went to public school you say eight from four is six; carry the one so we have 169, but in the new approach, as you know, the important thing is to understand what you're doing rather than to get the right answer here's how they do it now."