Fascinating thread. I too never heard the word regrouping, and thus skipped the intro to the question and got what OP daughter had; and the cavils on “borrowing” and “carrying” are amusing actually, as if they were problems in machine learning and semantics.
But of course with the concept as explained is perfectly clear and does flesh out what us older folks did, and its virtue, (over my dim distant education, perhaps) is nicely summarized by Ulf in #38.
The kids see “regroup” and it makes sense. Hell, I saw it, and I started puzzling on the set theory as part of 12-tone music theory.
Tell me, I’ve always heard the expression, including in this thread: is this an example of New Math? I realize it’s a huge topic and don’t want to go off-thread.
Brilliant cite on history of concepts of subtraction. Makes this thread make more sense. Also we can throw in “renaming” for the whole shebang of carrying/grouping/re-contextualizing numerals in different orders.
If I asked nice, could you tell me what you’re getting at with “distance reality?”
FWIW, now, following your comment on Brownell’s crutch, I have a handy excuse for why I suck at math.
“New Math” is what kids were taught starting in the 70s. In other words, unless you’re a lot older than I think you are, it’s what you call just “math”.
If I were older (or was older, speaking contemporaneously relative to the 10:56 PM event) what would I call it (or would have)? PS: I learned how to subtract in 1962-63 I think.
These terms still aren’t used in the UK now. Maths teaching has changed here but not in the same way. So the original question meant absolutely nothing to me at all. It’s been educational
Yeah, and the terms “gasoline”, “truck”, and “cookie” also aren’t used in the UK now. I’m pretty sure the actual methods are still the same, though we’d need to compare textbooks for 8-year-olds from both sides of the Pond to be sure (do you guys even use the same grade-numbering terminology as us?)
No need to be snarky. I’m just pointing out that you don’t have to be ancient to not understand this maths question. At first I thought it was just me being stupid (I’m great at arithmetic, not so great at more advanced maths) but no, it’s a language issue. I’m not complaining - like I said, it’s been educational.
I’m not sure if the methods are all the same, tbh, because that would require more knowledge of US maths than I have. Kids use numberlines a lot here these days.
Grades are different, yeah. For a kid who turns eight in that school year that’d be called year 3 (it goes nursery at age 3-4, reception, then 1, 2, 3 etc).
Sorry, didn’t mean to come across as snarky, there.
And I guess the year numbering is more similar than I thought: The year of kids who were 5 at the start of the school year, we call “kindergarten”, and we say “grade” instead of “year”, and not everyone goes to nursery school, but other than that, it sounds basically the same.
What about Harry Potter being in “year one” at 11 years old? Do you re-start the numbering at secondary school, or was that a break from the usual British usage?
Essentially, yes, though you don’t say year one (you say first year or first form) and it’s outdated.
The numbering system changed in 1990, before the first Harry Potter book was published but possibly after she started planning it, and I don’t think private schools all changed over. Before the 90s it was year 1, 2, 3 for ages 4, 5 and 6, then 1, 2, 3, 4 for ages 7, 8, 9, 10, then 1st, 2nd, 3rd, 4th, 5th, and 6th form (which went on for two years) for ages 11 to 17 (all by the age they’d start the year at). You’d make it clear by adding infants, juniors or seniors.
Huh, around here, “infants” is roughly synonymous with “babies”, and ends somewhere at around two years (at which point you’re instead a “toddler”). No eight-year-old would stand for being called an “infant”.
(a) some people were taught to rewrite the 10’s column when borrowing from it ("cross out the 3 and replace it with 2), and
(b) some people were taught to add -1 to the 10’s column when borrowing from it.
I /think/ that part of the new math was that you never re-write the numbers.
The genesis of New Math was that teachers thought math shouldn’t be taught: they’d never used it, and children should be discovering things, not being taught useless facts. The mathematicians reacted that children should be taught math in a form that formed the basis for understanding and further study, not a bunch of rote learned rules that just confused the issue. The military thought children should be taught enough math to be soldiers and scientists (to keep up with the Russians). The parents thought math should be taught the way they learned, and the press thought it didn’t matter what the argument was as long as there was an argument.
♫You can’t take three from two
Two is less than three
So you look at the four in the tens place
Now that’s really four tens
So you make it three tens
Regroup, and you change a ten to ten ones
And you add 'em to the two and get twelve
And you take away three, that’s nine
Is that clear?♫
“New Math” - Tom Lehrer
Honestly, until your explanation I had no idea that the question was meant to be a subtraction problem. I’ve never heard of regrouping before, and it doesn’t seem like how I was taught borrowing, either.
I think the teacher took the questions from the text book written for TEACHERS to read.
They were testing that the teacher fully understood what regrouping was. Not intending that the teacher test the students understanding of english grammar and the meaning of the word for unusual uses of “regrouping” with the same ontological question.
“New Maths.” Makes it even stranger…