Or just teach Jack how to solve problems like this in his head. I'm sure that would confound and astonish his teacher.
I remember this idiotic number line from my "New Math" days in the 1960s. It didn't work then, either. What's that saying about how you can't kill a bad idea?
Let me see if I understand. Math scores have been declining, we need to do something so let's make arithmetic more confusing and less relevant. There, that should solve the problem. Oh by the way, the last two or three thousand years of mathematics were wrong, it is just now that we are discovering the right way to do calculations.
Next lets fix this gender thing that we have had all wrong for eons.
I understand what they are doing, I do this in my head when I am estimating on the fly: Chop up 316 into 300+10+6, subtract 300 from 427: easy, subtract another 10 from 127, easy, subtract another 6 from 117. Happens in just a few seconds, but I'm juggling 5 numbers.
Nobody taught me, but I learned to do this from long association with using maths to make a living.
However ... it's not reproducible and verifiable, it's on-the-fly estimating. You have to write it down, show your work, let others check it. When engineers let mistakes creep into their work, bad things happen: products fail, businesses fail, investors lose money, people die.
As Mozart was forcefully told by Shikaneder in Amadeus, "Write it down, it's no good to anybody in your head!"
To write it down, use the compact form we all know and love, evolved from hundreds of years of careful pedagogy. That form is universal and compact, the numbers and operators only, no silly accompanying doodles to distract and obfuscate.
Common Core is an unproven hypothesis: teaching novices to think like experts do, without the long years of practice.
Yeah I understand what they are trying to accomplish here, and its basically an attempt to teach math in a manner more comfortable for people who do not have a mind trained to think systematically and logically.
The answer to that, of course, is to TEACH them to think that way, but the modern education theory is that you're violating young precious minds by directing them and teaching them things they aren't comfortable and at ease with.
But there's another perspective at work here. Common Core is an attempt to find ways to teach students who are doing poorly in school in inner cities and such in a manner that works for them, as if they're incapable of comprehending simple math. Its hard for them, because they've never had to learn to think rationally, but not impossible.
Yet if you don't really want people to think rationally and logically, if you want to avoid systematic thought and reason, its also useful to keep people in bondage.
Even if there is a method to the madness, how do you cope with numbers in the millions?
Making the simple and quick, complicated and laboriously slow, will increase the pool of incompetents. This will give the Lords of the taxpayers largesse a larger pool of jobless, disheartened dependents to give unearned favors to, in exchange for their votes.
THAT is the simple, elitist, enslaving arithmetic!
Spelling revisionism will be next. The name for these promoters of retrogression is spelled klbdnq and pronounced 'dumfux.' For simplicity and simpletons, the singular form is also spelled klbdnq, but pronounced 'dumfuk.' And for a spelling quiz, as Aristophanes might have said, "The 'P' is silent, as in diaper," as those who've held a suddenly smiling, relieved baby well know.
Spelling revisionism is already here. It's called "invented spelling." It's the reason so many people today are such poor spellers and have given up on trying to learn how to spell correctly.
The logical, oops, probably shouldn't use that word, extension of all the new teaching methods will be to not present, not teach anything, no grades, no class distinctions; sit anywhere you like, attend, don't attend, speak any language or make up your own.
Total anarchy and freedom from the shackles of antiquated and oppressive "education".
In fact, why have schools at all? folks will learn how to communicate and otherwise function in life situations as needed. Those that fail to adapt will fall by the wayside.
It worked pretty good for our Neanderthal ancestors, didn't it?
School is too valuable a tool for the left to control and reeducate our children, they'll never give that up. 8+ hours a day with young minds telling them everything you want them to know? No leftist will pass up that opportunity. Why do you think they fight so hard against home schooling or school choice?