2.5% isn’t quite right, but it’s in the right ballpark.
Since gas went up by $0.05, the question is really: $0.05 is ____% of $2.99 (or, without significant loss of precision, of $3.00).
I suspect that many of his students couldn’t get this far, which doesn’t yet involve any calculations.
$0.05 would be 5% of $1.00; it’d be half that (2.5%) of $2.00, and it’d be a third of that (about 1.67%) of $3.00.
My calculator gives me 0.05/2.99 = 0.016722408 = about 1.67%.
nm
3.04/2.99 = 1.0167 (rounding)
1.0167 = 101.67%
The new price is 101.67% of the original price, so gas went up 1.67%
Alternately, 3.04-2.99 = .05
.05/2.99 = .0167 = 1.67%
What she meant was “out of (the remaining) 60%” but you’re right that that’s not the same thing at all.
O. M. G. :rolleyes: This makes “But these go up to eleven!” sound intelligent by comparison.
best advice I ever got is part divided by whole.
the part is .05 and the whole is 3.04 or .05/3.04 =.016 or 1.6%
that simple mnemonic has served me well for 40 years. Taught it to my daughters and some cousins when they were struggling with percents in school. But you still need to understand markups and discounts. $8 item is discounted 10% so the discount is .80 sale price is $7.20
When I would give tests with questions like this, the students would whip out their calculators, which they were allowed to use, and start punching away. I was honestly interested in what they might be doing because the problem is so simple and calculators at the time didn’t solve equations. Turns out they would punch in numbers for X and work their way to the answer by trial and error. A surprising number used this method so I have to figure they learned it somewhere. I’m guessing SAT training.
I believe they had been misled into thinking calculators are necessary for math so they have to use it somehow and this method does work, eventually. In fact, with a little practice and some good guessing (like if the test is multiple choice), simple equations like this yield to this method easily. It also makes me cry.
There are many techniques for solving math problems and many ways of teaching math. If, as seems to be the case, you are insisting or implying to your child that the ways you happen to have been taught (or the methods that you now use) are the only right ways, and that her teacher’s way is wrong, you are probably just going to confuse her and harm her education. If you want her to learn well (and if you are not prepared to take the responsibility for full home schooling, which you are almost certainly unqualified to supply in most subject areas), then you would serve her best by finding out what her teacher’s approach is, and then supporting and reinforcing it, rather than undermining and sabotaging it.
Schools put a lot of effort and resources and, yes, expertise, into teaching math. Very arguably, in the USA, they put too much into it in proportion to other educational areas. Does this mean that all the pupils end up good, or even competent at math? No it does not. Math is hard, and hard to teach, and most people do not have much aptitude for it. Those few who do have an aptitude for it often seem unable to understand why everybody else is not like them, and they blame the teachers. In fact it has always been like this, and probably always will be: most people are bad at math, and probably most people always will be.
New ways of teaching math are constantly being devised and tried in order to overcome this problem, but none of them have ever done so to any very significant degree. Some teaching approaches may work for some kids and some for others, and most do not work very well for most. Unfortunately schools do not have anything remotely approaching the resources to tailor teaching methods to individual kids’ needs, even if they had any way of knowing in advance what would work for what kid.
Working at Foot Locker is a business.
Thanks for that. My point wasn’t to undermine or sabotage the school, only to point out that the way they taught didn’t make sense in any functional useful way. I won’t repeat what I put in the OP, but it seemed they were more concerned with the abstract of numbers instead of teaching math.
But, I will say this, she would have never learned the times tables in school, because they refused to use it. I taught her that. While the other 5th-6th graders were using calculators to do multiplication, she was doing it in her head. She can do division multiple ways, how school taught her, and how I showed her. She can make change in seconds, and figure out percentages quickly. And she hates math, can’t stand it.
I know I’m not qualified to teach, and never claim to be able to either, but I do know that I am capable of teaching my child many things, scholastically or otherwise, and she is my proof. She is now 20 and an intelligent young lady, book wise and real world wise. Between school and myself I am confident she can handle what future may come.
I never argued that math was easy. I also understand that some people hate math, or have a difficult time with it. That isn’t the point of my OP.
I find it interesting that today, many countries (at least 25) have better prepared students mathematically than the US does. Which begs the question, why do we import so many scientists, engineers, etc. on visas to do what the US used to be so good at?
I go back to my original question - have the schools failed to teach kids math?
My son just started kindergarten this year. Surprising (to me at least) he is bringing homework every night (I got my first homework in 4th or 5th). It is mostly stuff I did in 1st grade, writing, reading, counting, simple addition.
The teacher did recommend some math apps (everyday math by McGraw Hill). So far the two I have tried just seem to be fun ways to do normal math. One is about number lines, and the other is the multiplication table (1-12). That is a little beyond him, but he is learning. He can do the 1, 2, 9, and 10s. The rest I help him with and it lets him practice his addition.
I plan to keep an eye on this going forward, but does not look like all schools are abandoning math.
One thing to keep in mind as far as the OP goes, at any time in the past 80 years if you took all 18 year olds and tested them on this a large percentage would have failed. 50 years ago, it didn’t matter as much because only a small percent went on to college. Now, there are very few dependable ways to financial security without a degree, but that doesn’t mean the schools are doing a worse job. We just changed the curve on them.
While the ways in which they’re teaching math to my daughter are very different from the way I learned math, it’s not at all accurate to say they are failing to teach our kids math.
Are many kids failing to *learn *math? You betcha. But as you see, this is a problem that goes back more than 40 years (to Dopers who were teaching remedial math in college in the 80’s), and today’s “weird” math programs are intended to *better *teach math.
Yes, it’s much more conceptual with less emphasis on rote memorization. Because what they found with my cohort (graduated high school in 1992) was that we were fair to middlin’ at worksheets, but horrendous at application. We may know (or have once known) our times tables, but we can’t fookin’ make change when the cash register goes down. This isn’t “kids today”, this is people in their thirties.
Conceptual learning is yet another experiment in the education of math. There have been many. There will be more. But please don’t forget that there are just some crappy students, and social promotion and lax college entrance requirements are at least as much to blame for many of these stories.
What on Earth could conceivably be wrong with learning the multiplication tables??? This thread is rife with the harrowing details of what it means not to have learned them. My heart goes out to parents and students who are subject to mass educational malpractice by at least some sections of our educational system. The parent you are replying to was fully within rights to challenge malpractice, and, since you brought it up, would be perfectly right to correct it as far as possible by supplemental home schooling.
The “new” ways of teaching math were just coing into vogue as I was entering college in 1967. Thank God I was spared. Have US math scores ever been anywhere except rock bottom or close to it among the 30 or so most advanced nations since then? I do not think so. These “new” ways of ours are not getting the job done, and that is that. Maybe one of these days we will work our way out of the present culture of value-subtrtacted educational malpractice we have built for ourselves, but it won’t take place as long as the malfeasors recieve nitwit support such as typified by Mr. njtt’s post above.
Picking nits: Except that the question was what was the percentage increase from the previous day’s price, so 0.05/2.99, or approximately 1.67%.
The third paragraph is an interesting point, one I hadn’t considered. Times have changed, the market has changed and jobs have changed. The curve would have changed, realistically, and the schools are trying to catch up. I do wonder if having the federal government dictating curriculum is, in part, a cause for the results I think I’m seeing, and some have commented on in this thread. I’m not picking on the feds, it just makes me wonder if the further away from the students that decisions are made, the less effective they would be.
And it seems WhyNot followed up nicely with:
Hmm. Maybe I am looking at this the wrong way round. Perhaps njtt is right that most people are just not good at math, and it is reflected badly on the schools?
I’m curious, is the ability of the teacher hampered by the curriculum enforced by the administration of the school, district, state, or feds? I’ve read stories where teachers went against the ‘approved curriculum’ and ended up with better results. Would teaching styles be a reason for the difficulty or success? I know math can be boring as dirt, but I remember one professor in college who made it fun and interesting with his style. Perhaps this is part of it?
We’re at least two “news” past the way they taught math in 1967. Three, I think.
Here’s the transitional plan for the curriculum being phased in grade by grade in Chicago Public Schools. Here’s the programthat makes the foundation of that curriculum being phased in.Nothing like I learned in the 80’s, much less what you learned in the 60’s.
Our teachers must use Everyday Mathematics (in those grade levels for which it’s been rolled out in the school district), as well as having the freedom to add anything they’d like to add from other sources, some of which are more focused on rote memorization - my girl calls those “the easy pages”. 
[not-so-stealth brag time]
My daughter can do fractions and fundamental algebra. She can calculate the volume of solids and tell time on an analog clock face as well as a digital, including telling you what time it will be “in three hours,” or was “12 minutes ago” - she can even add minutes past the hour mark and get the hour switch right. She can do addition and subtraction of as many numbers of as many digits as you can feed her. She can count by 1’s (of course), 2’s, 3’s, 4’s, 5’s and 10’s. She can multiply one and two digit numbers. She can do probability predictions for dice rolls and spinner games. She can calculate multi-item purchases and accurately make change.
Most importantly, she can do most of these things in at least two different ways (in her head, on her fingers, with manipulatives, with a calculator) and she can tell you WHY she’s doing what she’s doing. She *understands *math, not just regurgitates it.
She’s seven.
There’s hope for the future yet 
Well another thought on the matter of the “old” vs “new” styles of teaching:
I mentioned that in everyday life I’m considered “good at percentages” by people who are, frankly, shit at percentages. I always thought I was bad at all things maths-related. It was only when I started comparing to the real world that I realised everyone else was shit.
I think this is the reason: I went to a facist* primary school. Their own description was “old-fashioned education”, ie repeating times tables until you can dream them backwards, no colourful pictures. And certainly no positive feedback for the little whimps. So it was miserable, and I was traumatised for years to come, and if someone calls me stupid I will still cry, BUT it worked.
My peers can’t calculate how much something will cost if they get 19% off, but I can. And so can my sister, and others I know who went to that hellish school.
I’m sure there are many perfectly sound ways to teach basic maths. And I’m sure that personal aptitude has something to do with it. But I do think just memorising times tables is extremely important. And just doing boring long division over and over has its merits.
*pop-cultural meaning of facist. They were mean, hateful bullies. They hated children, all of them.
ETA: WhyNot, your daughter is a genius, seriously. Wow. Seven??
See, this is my problem with some of the silly “mnemonics” they teach in math classes – Percent problems come in a variety of permutations (of which you’ve mentioned a few), but “part divided by whole” doesn’t necessarily solve them all. Now you’ve got to memorize just which form of problem that mnemonic does solve, and you still need to know some actual, you know, algebra to recognize and solve the others.
Same bitch I have with the lame “FOIL” rule. Learn that by rote, and you can do all the (a+b)(c+d) problems in the world. But just throw one (a+b)(c+d+e) problem at the poor little dears, and they are lost. And Og help [del]us[/del] them if we ever have (a+b+c)(d+e+f+g)
You don’t need to memorize anything. All you need to do is provide the correct answer to the given question, and none of this is difficult; it’s grade 9 or 10 math at most.
I’m struggling to find any difference at all in the approach to solving these equations.
I teach AP Economics, and we do a lot of basic arithmetic. One thing I’ve noticed is that kids don’t transfer concepts very well between courses: sit them in calculus class and ask them to add 20% to 240, and they can figure it out without a problem (though they may still reach for a calculator: they are bad at basic math). Tell them that the price index rose from 240 to 284 and ask what the inflation rate was, and they freeze. They don’t know how to think math in a social studies room.
I will also say this: there is no divide between repetition and conceptual learning. To teach concepts, you need to repeat yourself. A lot. But people tend to remember the one time when you said it and it all clicked for them, and forget the 562 other times you said the same thing in a slightly different way. But those 562 other times laid the foundation for the one time when it clicked.