common core math
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It's not Maths; it's counting. Everyone can count, so it's really easy. Now subtract 7 from 472326598458412365452131236525897456321452453698736985215457. Call me next week when you're done.
I wanna be a eunuchs developer! Pass me a bread knife!
string s = "472326598458412365452131236525897456321452453698736985215457" ;
int i = s.IndexOf ( "7" ) ;
s = s.SubString ( s , 0 , i ) + s.SubString ( s , i+1 ) ;(Or something like that.)
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Kent Sharkey wrote:
Here's a post about the merits of it[^], or at least why it's not really that bad.
I see how using the base as a reference point is a good thing for mental math; I do that already. But they way they implemented it is just retarded. In the case of
325 - 38, why not just do something more like325 - 40 + 2to get the answer? Or hell even(325 - 25) - 40 + 25 + 2? You get the benefit of it being easier mentally without all the extra crappy steps.Jeremy Falcon
It seems to me that those of us who are really good at mental arithmetic have always solved problems differently depending on context. The reality is that we rarely use long subtraction, but use all manner of shortcuts. It's a little like programming: We take a first look at the problem; determine a method, based on experience; we implement. As we learn new tricks and put them into practice we add them to our list of methods, sometimes replacing old ones (I still, rarely, use DOS batch file coding!) The trouble with teaching maths using that approach is that kids need to start learning one way. If an experienced maths teacher says that they found it easier to teach this way, I'd take his word for it. Bad explanations and bad examples only serve to reinforce our prejudices ("That's not how I was taught to do it!") As programmers, I would hope that we'd be open to consider new techniques? I do think that there is merit in learning the "granny" method too, because sometimes the "simpler" tricks break down and the problem is too complex to solve with a hack!
Life is like a s**t sandwich; the more bread you have, the less s**t you eat.
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Um...you probably should have chosen a more difficult problem. :p
We won't sit down. We won't shut up. We won't go quietly away. YouTube and My Mu[sic], Films and Windows Programs, etc.
That's the point. Using the common-core-counting method, it would take forever! Not using the common-core-counting method, it takes as long as it takes to see what the last digit of the number is.
I wanna be a eunuchs developer! Pass me a bread knife!
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How about I use a calculator, and don't call you. :)
If you need a calculator for that, you should call a private arithmetic tutor.
I wanna be a eunuchs developer! Pass me a bread knife!
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I was going to pipe up with the same explanation that everyone else did, It's a good way to do subtraction in your head. I learned that and more as a child. The common core doesn't seem that weird to me, but it sucks that they don't have any physical materials to work with like I did. For example this is one way I learned multiplication: Checkerboard[^] This is what I worked with for addition: Bead frame[^]
Curvature of the Mind now with 3D
I can't watch YT videos at work... oh the tease! :laugh:
Jeremy Falcon
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I think that is stupid way to do math. Sorry, but that is how I feel.
No need to apologize man. I like the premise personally, I just don't particularly see how the implementation is good.
Jeremy Falcon
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It's not Maths; it's counting. Everyone can count, so it's really easy. Now subtract 7 from 472326598458412365452131236525897456321452453698736985215457. Call me next week when you're done.
I wanna be a eunuchs developer! Pass me a bread knife!
Mark_Wallace wrote:
Now subtract 7 from 472326598458412365452131236525897456321452453698736985215457.
42326598458412365452131236525894563214524536983698521545Tada!!Jeremy Falcon
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Hmmmm... 38 - 25 = 13 , and 100 - 13 = 87 , so 287 .
Well of course. But for me 38 - 25 takes more effort than fiddling the numbers in my head, either by adding or subtracting to reach easier to work with numbers, or breaking it down into smaller sums, for example
((30-20) + (8-5))(although that requires me to remember more numbers at a time). If I had to do mental arithmetic more than few times a month (beyond counting change) than perhaps I'd have an easier time with it. I'd also like to point out that I don't sit there and think "Perhaps if I add two or three here, and then..." the route to the answer comes without much thought. -
Can anyone really explain to me what this is all about? So far it seems to be a bunch of hoopla that makes things harder and not better. In all fairness I don't know much about it how all works, but when I see something like this[^] I have to wonder what was being smoked when they came up with it.
Jeremy Falcon
Someone got the idea into their head (Can you smell Ph.D. dissertation?) that students need to understand HOW they got the answer not just the mechanics of getting the answer. Trust me, there are a whole bunch wilder things buried in there. Some bizarre 5th grade thing my wife showed me used area to figure out some calculation that had NOTHING to do with area. I agree with the idea of common core, kids in the first grade should know this list of stuff, but there all sorts of problems with the ideas on how to get the information into those little skulls full of mush. Kids don't memorize multiplication tables anymore so they have to figure out each part of a two digit by two digit multiplication problem.
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Kornfeld Eliyahu Peter wrote:
it's not the way I ever done things
I agree it's weird to anyone with more maths ability than a gnat or gnu, but how often has something like this happened: Green Grocer: That'll be £7.93 please. Me: [Hands over £10] There you go, thanks. Green Grocer: [Hands over 7p] - eight quid [Hands over £1] - nine quid. [Hands over £1] - Tenner! That's the basis of the insano-method
Alberto Brandolini:
The amount of energy necessary to refute bullshit is an order of magnitude bigger than to produce it.
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One criticism I have heard a lot about some 'modern' education techniques is the emphasis on 'research'. With the advent of the internet some children are being encouraged to look everything up and 'discover'. In some cases there has been a strong move away from rote learning or the learning of facts. It's certainly something I have seen a bit of, where giving a person a task they rely more on their opinion than on hard evidence. Evidence they can gain by looking in detail at what is happening. My take on it is that you need a solid foundation in basic facts such as memorising simple multiplication tables for simple things. Then extrapolating from those basics to more abstract concepts when you come to things like calculus.
“That which can be asserted without evidence, can be dismissed without evidence.”
― Christopher Hitchens
It much older than the Internet - it's called Pupil-Centred Learning and has been around in one form since the 70s to my knowledge, probably longer. This is interesting [^] as it suggest student centred learning can't work until you are about 11 as it requires logic.
Alberto Brandolini:
The amount of energy necessary to refute bullshit is an order of magnitude bigger than to produce it.
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The problem with this system is that it works for subtraction and it is very easy, probably easier then the traditional carry method we all learnt. But that is it. It ONLY works for subtraction. The multiplication method is different, division is different. In other words common core ignores what is common. A + B = C --> C - A = B & C - B = A A x B = C --> C / A = B & C / B = A And as soon as you move into negatives, algebra and real geometry it's useless.
Presenting a reasonable, rational argument? Do you belong on the Internet? ;) Yeah, I was thinking of it in isolation (where I still think as a first method it makes more sense than the traditional method). However, as you point out, other than in isolation it doesn't make sense. Plus - as others have pointed out - this is being taught to older kids who supposedly have already integrated the older method, confusing them. Definitely makes less sense to me now. Fortunately, no kids in the system.
TTFN - Kent
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If you need a calculator for that, you should call a private arithmetic tutor.
I wanna be a eunuchs developer! Pass me a bread knife!
I honestly just looked at the long number and started typing. My point was that if the numbers/maths are complex then use a fucking calculator. Move out, draw fire. No need for this bizarre, bullshit way of doing arithmetic. :)
