Possibly related, but son is offended by algebra. I think he believes his grounds are based on logic, but they are really aesthetic. Anyway, he will tell you the right answer and then explain why that should not be the right answer.
Reteaching is key; it does occur in our current system, but only during freshman year of college remedial algebra. That's too late and leaves too many out.
A divided by B means how many copies of B you can fit into A. That works perfectly well for "5 divided by 1/2".
And when it's taught in remedial settings, it's (usually) taught exactly the wrong way - rushing through the algorithms as fast as possible because there's too much to cover, and this is old, so it can be barrelled through.
Remedial courses and college algebra are taught so monumentally badly it's astonishing. Good teachers trapped with terrible, terrible books which organize courses in terrible, terrible ways.
I realize that I don't have a good off-the-cuff explanation of multiplication which covers both (1) and (3).
It makes wonder about something. The way that I was taught math in elementry/middle school the "equals" sign had a whiff of causality to it:
5x3 = 15
Is presented as having an (implied) temporal dimension. That you start with 5 & 3 do something and end up with 15 as the result.
By contrast, in algebra (and everything afterwards) the equals sign is more like scales/balance -- you can do whatever you want to either side of the equality as long as you do the same thing to the other side.
So, with that in mind, I wonder if there's some way that you can get across the idea that there are literally an infinite number of ways to write an equality (I'm going to use "x" for multiplication rather than * because I think it looks less "mathy" which is what I'm going for).
2=2
1x2=2
4x0.5=2
2=6/3
2=100x0.02
Those aren't solutions to a function or a problem; but they're all true statement. And it's worth learning* that being able to say "this is true" is the basis for a lot of math.
*Or, at least, being comfortable with that idea was a big advantage for me in math.
3, con't: Not to say that's the only interpretation or useful for every circumstance, but it's a good intuition that ever fluent student should be able to use, alongside other models. There's a unit of instruction of our tutoring software that uses a "parts of whole" model to realize that intuition. Or something like that; it was designed by cognitive scientists who've thought much harder about it than I have.
4: I have been amazed by how many sections we'll have in a remedial course. Back when we were associated with Evil Giant For Profit University, their remedial course was the single greatest cause of students failing to complete a degree. There's so much to learn, in too a short time, by people who are coming into this with pre-existing difficulties (including those who have been out of school for years).
I think the big mistake is not teaching set theory in first grade so that they can build on it as they get older.
Those aren't solutions to a function or a problem; but they're all true statement.
Exactly. Then they can spend all their time explaining why that's a stupid thing to have a symbol to do until you have wasted two hours of a Saturday.
Anyway, the Inuit have a hundred words for three fourths.
The real problem is that Ohioans have decided "5/3 Bank" is pronounced "Fifth Third Bank."
And if you ask for One and Two Thirds Bank, they don't even get it. I've tried.
Our origins go back to the Bank of the Ohio Valley, which opened in Cincinnati in 1858. In 1871, that bank was purchased by the Third National Bank. With the turn of the century came the union of the Third National Bank and the Fifth National Bank, which eventually became known as "Fifth Third Bank."
5 is a big thing in the way math ed people want math to be taught these days. Students taught traditional methods do tend to see "=" as an arrow, and they act as though it means, "And then you get..." You see this in calculus constantly, where students set the original function equal to the derivative, because what they're thinking is "and then" not "equals".
There is in fact emphasis on things like "how many ways can we write 15?" and things like that, to address this.
I don't really know what's done in reality. I know what my math ed friends say are best practices, I know what's done at the schools my kids go to, and I know that the white flight districts nearby have (deliciously schadenfreuden) old-fashioned shitty math instruction. But I don't know what's done nationwide.
7: you laugh but I swear there must have been some 70s shit with this idea. that would be so 70s.
OP: heebs, what do you feel is the most concise explanation of four congruent with the previous explanations 1-3? or not, even, just the easiest? I remember gnoled darb once explained in in such a way that I thought, "holy shit that's easy" but now I don't feel I could do as good a job now say, to girl y, re: algebra, despite being able to do the operation fine. I think most american math students learn it that way: an operation. like a military order: do this to these numbers in this order. not much mental space is even left for understanding. it does retard remedial math at the college level; my sister struggled badly with fractions in algebra but the teacher spent zero time on fractions.
"and then" always makes me think of Dudes, Where's My Car? Very underrated movie.
14.1: The 70s were sort of over in that sense before I started school, but I knew from the older siblings of friends that my high school used to work on a "packet system" where the students were largely self-directed, entirely ungraded, and, if you believe the stories, mostly stoned. I asked my dad how that ended and he said parents started to get concerned that their kids were having trouble being accepted into college, so they stopped it. On reflection, I think that was his way of saying he thought it was nuts and killed it. He was certainly on the school board when or shortly before it died.
I recall having a lot of emotional anxiety when I first heard about division because my father (who was trying to teach me stuff early) explained it as "multiplication in reverse." He didn't teach me about reciprocals so I couldn't comprehend what reversing a binary operation could mean. (Obviously I knew about subtraction but the addition is to subtraction as multiplication is to ___ is a conceptually hard analogy; at least subtraction is still linear.) That was the only model he gave me and that abruptly ended my accelerated learning.
So I whole-heartedly endorse "number sense" related exercises and things like described in 14. There's not one way to know this, and which way is most intuitive will differ from person to person. Rigidity in instruction can't be built upon.
Ideally, I think remedial math should be taught with 1-on-1 tutors, so the tutor can focus on the specific things the student didn't get the first time, rather than trying to teach a class where you are trying to cover everything any student is having trouble with. It would be ridiculously expensive, though.
Back when I was doing math tutoring, I had one kid who was having a lot of trouble with algebraic fractions, which I diagnosed as not really getting fraction manipulations. I printed out a handful of fifth grade worksheets covering fraction addition/subtraction/multiplication/division, went over the basic ideas of each, and had him work through one worksheet of each kind before we met again the next week. When we got back to the algebraic fractions, he got the ideas right away, and had no further problems with them. Not every tutoring assignment was that simple, but when it works, it can make the tutor feel they have super powers.
14: hmm, good question.
My first answer was terrible - I was trying to make it work with lengths of string, which is how I'd actually think about it.
5/3 = 5 inches of string, divided in three equal pieces; how big is one piece?
5/ 1/2 = 5 inches of string, assigned to be equal to 1/2 of a mystery unit piece; how big is the mystery unit piece?
I believe the "right" answer is something like:
For 5 divided by 3:
How many 3s fit inside a 5? You can fit one 3, and then 2 units of the next 3. So 1 2/3 threes.
For 5 divided by 1/2:
How many 1/2s fit inside a 5? You can fit 10 copies of 1/2 inside a 5.
The secret is to teach it in term of dividing up pizza into slices. That's something that everyone can relate to.
18: Even so, I'd bet 1:1 tutoring for things like this would save money under some sort of accounting regime that took into account the total benefit to the economy of people who actually understand basic math concepts. Not that that's possible.
It heartens me that 3.2 is in alignment with 19.
19 is about how I was thinking about it. Multiplication I usually think of in terms of regular grids of dots or something (and is also how I think about and explain prime numbers - a number of dots you can't turn into a regular grid). For fractions the dots have to become divisible objects, maybe circles, and so for the last part the visual approach would be "how many half-circles can I fit in five whole circles"?
(My son and I have been working through the "Bedtime Math" books, which are basically exercises in extracting simple arithmetic problems from word problems. I'm going to have to start looking for books with more conceptual trickiness)
I'm going to have to start looking for books with more conceptual trickiness)
They're logic, rather than math problems, but I have fond memories of the Raymond Smullyan books (and I'd guess they're targeted for older kids, but I just wanted to put in a plug for them).
7: The New Math! I got the tail end of that in elementary school, just as they were phasing it out.
24: That doesn't sound like it's going to top Harry Potter any time soon.
So, I was at a birthday party this weekend and two parents had a long, involved conversation about remedial math. One of them was a high school math teacher at a school with very few kids on a college track. I could have learned a bunch if I had listened.
The gist of the conversation was that's there one way of doing it that hurts one group of kids and another way of doing it that hurts a different group of kids.
29: In the interest of equality, they should do it both ways so that both groups get hurt.
I agree with you so much! If I could change one thing about high school math it would be removing calculus and adding a course on fractions and inequalities.
One of my favorite mathematicians, Paul Levy (best work published when he was over 50), made a nice observation about fractions:
https://en.wikipedia.org/wiki/L%C3%A9vy%27s_constant
31: Statistics is what high school needs.
I think statistics is singular in this instance, but it's possible that further instruction in grammar are what I needs.
Am I the only one who initially read those questions as "one-point-five times three; two-point-five divided by three; etc."?
31: What percentage of the kids have ever seen a calculus?
Do they even know it's calculus?
Unless you're going to sleep with your students and they all have aunts with vicious minds.
James Madison warned of the danger of fractions.
If Dave W had taught me at age 14 my entire life would be different, and far better paid.
Anxiety about maths was so prevalent in the seventeenth century that calculus was originally nicknamed "the method of fluxions" after the symptoms it provoked in nervous students.
It's all clear when young Hornblower is explaining it, but when I try it on my own it's just gibberish.
45: I am immensely fond of the promotion interview scene in "The Examination for Lieutenant" in which Hornblower, as a result of some frantic last minute study, is utterly unable to think of anything except rhumb lines; the interview is going very badly indeed and is only saved by the unexpected arrival of a Spanish fireship.
I feel that my own education would have been greatly improved by a few fireships.
Give a girl a fireship, and introduce her properly into the world, and ten to one she has the means of settling well, without further expense to anybody.
In the Bronze Age, when I was learning fractions we were taught:
1. A number over another number is a quick way of saying "divided by";
2. Whole numbers are just the same as that number over 1, because if you divide a number by 1, you get...;
3. If you want to divide by a fraction, flip it over and multiply, because easier;
4. "But, miss, why does point 3 work?" "We'll come to that later."
Surprisingly, I too was taught in the bronze age.
By now you're aground, sir!
No, the coastline has eroded in the interim.
49,50 53: Perhaps the Bronze Age never ended.
YOU BETCHA.
OT: Monopoly is, clearly, a terrible board game. In part this is because it was invented as a warning to show how grindingly awful unchecked rentier capitalism would be.
Could one design a version of Monopoly - ideally, involving as much as possible of the existing set, so really we're talking about just a new set of rules and maybe some new cards - that a) is more fun to play and b) promotes some fairer way of organising society?
Instead of everyone aiming to buy as much property as possible and make loads of money out of rent, perhaps you could set it up so that the aim was to get as much property as possible into the hands of owner-occupiers or non-profit-making social housing organisations.
Diminishing marginal utility? The more money you have the less it's worth (or just tax?)? Deflationary effects? Hard to implement.
56: A cooperative game where the goal is to divide up the property as fairly as possible among the players, and everybody wins! '
No one wants to play this game, and that's why socialism is doomed.
There are cooperative games out there, and they do very well: Pandemic is probably the most famous.
Maybe set it up so that rent sucks money out of the economy in some way? And thus impoverishes players instead of making them richer?
57 last: concentration of property above a certain level reduces everyone's rent automatically, thus making everyone poorer? Aim being then not promotion of justice as such, but internalization (God help me) of Keynesianism.
I don't remember how the game works. Everyone starts with the same amount, you can buy property, passing players pay rent, and that's your only income stream?
Every time you pass Go you put money from the bank into the Community Chest- that's how well the economy's doing. But every time you land on a property you have to pay rent to the bank. Once the first player makes it all the way round, you divide up whatever's left in the Community Chest equally between you. You can spend that on buying out property - after it's bought out, it's publicly owned and you don't have to pay rent on it any more. The winner is whoever manages to get the most property into public ownership.
61: pretty much, yes. You can build houses on property you own, and that bumps the rent up.
This sounds about as fun as the "Math Gran Prix" Atari game I got for Christmas one year. Let's get ready to cooperate!
62: So basically you spend your tax rebate to buy out property? I don't know it'd make a good game. How about, progressive and redistributive taxes, so one's income is rent plus public support; plus the rent-reduction mechanism. Then, as one accumulates more property, one pays more in tax, while one gets less in rent, and in public support, as one's tenants can afford less in tax.
Could one design a version of Monopoly - ideally, involving as much as possible of the existing set . . .
I think I've seen versions like this advertised, let me see what I can find.
56: That's the problem with you liberals. You want to give everybody trophies.
Call of Cthulu is a fun game, though.
I found anti-monopoly but it sounds like it takes even longer than the original game.
But it was interesting to learn that:
It turns out that Monopoly's origins begin not with Darrow 80 years ago, but decades before with a bold, progressive woman named Elizabeth Magie, who until recently has largely been lost to history, and in some cases deliberately written out of it.
...She created two sets of rules for her game: an anti-monopolist set in which all were rewarded when wealth was created, and a monopolist set in which the goal was to create monopolies and crush opponents. Her dualistic approach was a teaching tool meant to demonstrate that the first set of rules was morally superior.
And yet it was the monopolist version of the game that caught on, with Darrow claiming a version of it as his own and selling it to Parker Brothers. While Darrow made millions and struck an agreement that ensured he would receive royalties, Magie's income for her creation was reported to be a mere $500.
62: if a player goes bankrupt, they become an agitator. Take one of the weapons from Clue[do] to use against the rentier class.
I haven't played Anti-Monopoly in many years, but I think it has a politically correct theme.
Any player who gets pwned transfers all assets to the pwner.
I suppose you could play Monopoly on a Risk board and call it "Colonialism".
I think the key is mimicking the deflationary effect of inequality. Maybe you could have a set of NPC tokens moving around, paying rent; as rents rise, some of them drop out, and rents received consequently fall.
76: Have you read The Steep Approach to Garbadale?
my best friend and I used to play cooperative two person monopoly within larger monopoly games. it drove everyone nuts. we'd give each other money and property etc as needed, spontaneously. one or the other of us would nearly always win.
That's how I got thrown out of the casino, except with poker.
Could one design a version of Monopoly - ideally, involving as much as possible of the existing set, so really we're talking about just a new set of rules and maybe some new cards - that a) is more fun to play and b) promotes some fairer way of organising society?
Your constraint about the existing set rather spoils things, but there are plenty of good games that promote alternative ways of organising society, or at least show up the flaws in capitalism without being bad games. Chinatown springs to mind. Particularly timely given how the US president's ostensible deal making prowess was key to his appeal. To non-racists, anyway.
As a kid I did quite enjoy Careers in that it at least had Love and Fame as part of the overall equation for winning. (And I don't believe it had any "fuck your competitor" aspects other than the relatively mild one of using up a degree/profession.)
A fun party card game we like is the Great Dalmuti. It specifically recognizes and provides advantages and disadvantages based on your position. It does include a "Lesser Revolution" where for that hand the primary advantage is wiped out, and a "Greater Revolution" where top goes to mbottom and vice versa.
This kind of thinking borders on being Charles Murray-style race science, in my opinion, and like race science, it exists to justify and minimize material disparities that exist in America. Plenty of children in America somehow manage to learn fractions just fine in English. They're just disproportionately in segregated schools -- public or private -- in wealthy neighborhoods with wealthy classmates. The only cultural custom that matters here is the cultural custom that we simply do not care about public education for the many in America.
Wait, what kind of thinking borders on race science? Thinking that fractions are genuinely difficult and should be taught better?
Wait, what kind of thinking borders on race science?
Suggesting variant versions of Monopoly.
Plenty of children in America somehow manage to learn fractions just fine in English. They're just disproportionately in segregated schools -- public or private -- in wealthy neighborhoods with wealthy classmates.
This is surprisingly not true! I'm sure that there are class differences - poverty interferes with ability to learn in school - but in this neck of the woods, the wealthy white flight towns to our west and south have super shitty math education programs, comparatively, because the parents know best, and they want math taught exactly like they larnt it back in the 80s.
88, I am ashamed to admit, immediately led me to start thinking of rules for Racism Monopoly. If you end your turn on a property owned by a white player, you go directly to jail.
We had a bit of a natural experiment on these issues with my daughter, who spent 1/2 of first grade in an ultrafancy private elementary school and 1/2 of first grade in a 80% free-school-lunch school where she was literally the only white kid in her grade. The math instruction was much better, and obviously better, in the low-income public school, because there was a dedicated teacher following a well-laid-out new curriculum.
*she's now in another ultra-fancy private elementary school, but with better academics IMO than the first private school, but only for social reasons and things unrelated to the core academic curriculum. Even now I don't think purely in quality of things like math instruction there's much of a difference (though there is a difference in the way in which the kids/parents care about math).
They weren't teaching fractions in first grade, obviously.
Of course. They'd call it 6/6th grade otherwise.
No, the thinking that the reason American kids underperform the Chinese is that we don't say "out of three, four"
Let 999 out of a thousand flowers bloom.
Though Heebie is of course right that plenty of parents have hostile attitudes towards education that are ultimately destructive to everybody. Heebie is right about everything, math education-wise.
Hey RH and other los angelenos, stay safe down there! looks awful sending much sympathy. Don't breathe in more of that shit than you absolutely need to, it is super hard on the bod and not just the lungs (mum looking at a pacemaker and heart monitor installation following cardiac incident about a week after worst of fire over ☹).
The kid seems to have taken on board sufficient maths but in frenchy ways, but a bit of light khan academy revision resulted in a somewhat absurd jump in psat score leading me to think even more the whole thing is some kind of ridiculous con.
(I am really stressing out over the testing-application iditarod but along an axis of personal trauma and distress so far removed from and antithetical to the wider culture of UMC parenting ... partner, kid, friends keep on having to talk me down off various ledges. So much of all the current wrongness in the world seems baked into this shitty process, the SAT subject test for "English literature" being fucking multiple choice, my god the mindless rampant credentialism.)
95: 999/(111/11) luftballons, würdest du bitte.
I can only just believe the idea of a multiple choice test for English LIterature, but it would explain a great deal about the modern world.
They wouldn't dare try that shit on Greek literatureσ
Thank you, NW, it is horribly reassuring that someone else shares my incredulous horror. I am having a hard time summoning sufficient reserves of cynicism in navigating this process.
It reminds me of the "My Dinner with Andre" video game.
103 That's my favorite New Yorker cartoon.