Common Core Subtraction
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In the U.S. we're currently suffering through "Common Core" teaching methods (I'll leave it to you to google "Common Core". Most of you remember the way we were taught to do subtraction:
32
-12
___
20This is the way Common Core teaches the same problem:
12 + 3 = 15
15 + 5 = 20
20 + 10 = 30
30 + 2 = 32
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20I understand how they got there, but I DON'T understand how that's a better way to do it. :wtf: Maybe it's because a minus sign promotes negative thoughts about math...
".45 ACP - because shooting twice is just silly" - JSOP, 2010
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You can never have too much ammo - unless you're swimming, or on fire. - JSOP, 2010
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When you pry the gun from my cold dead hands, be careful - the barrel will be very hot. - JSOP, 2013Common sense says: If it ain't broke, don't fix it. That's what we got here: failure to apply common sense. "Old" style mathematics got a couple of guys on the moon, lots of stuff in space and all these computers/devices we like so much. That means at least some of the old style calculations got it right. Change for the sake of change is just plain stupid.
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You count up from 12 to 32, using easy incremental steps 12 + 3 = 15, then 15 + 5 = 20, etc util you get to 32. So it could be done shorter as well: 12 + 8 = 20 20 + 10 = 30 30 + 2 = 32 ------------ 8 + 10 + 2 = 20
Jacquers wrote:
You count up from 12 to 32, using easy incremental steps
And what exactly is this "Incremental steps"? Who says you cannot count up from 12 to 32 like this? 12 + 20 = 32 » 32 - 20 = 12 or » 32 - 12 = 20 and as such 20 - 12 = 8 (How do I know that? Well take 32. 3 X 2 = 6 + 2 = 8) :rolleyes: I mean even easier still is take the original problem 32 - 12 = ? 3-1=2_ 2-2=_0 » 32 - 12 = 20 :wtf:
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It is almost as though they are deliberately enstupidising children.
--------------------------------- Obscurum per obscurius. Ad astra per alas porci. Quidquid latine dictum sit, altum videtur.
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In the U.S. we're currently suffering through "Common Core" teaching methods (I'll leave it to you to google "Common Core". Most of you remember the way we were taught to do subtraction:
32
-12
___
20This is the way Common Core teaches the same problem:
12 + 3 = 15
15 + 5 = 20
20 + 10 = 30
30 + 2 = 32
____
20I understand how they got there, but I DON'T understand how that's a better way to do it. :wtf: Maybe it's because a minus sign promotes negative thoughts about math...
".45 ACP - because shooting twice is just silly" - JSOP, 2010
-----
You can never have too much ammo - unless you're swimming, or on fire. - JSOP, 2010
-----
When you pry the gun from my cold dead hands, be careful - the barrel will be very hot. - JSOP, 2013 -
It is almost as though they are deliberately enstupidising children.
--------------------------------- Obscurum per obscurius. Ad astra per alas porci. Quidquid latine dictum sit, altum videtur.
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Common sense says: If it ain't broke, don't fix it. That's what we got here: failure to apply common sense. "Old" style mathematics got a couple of guys on the moon, lots of stuff in space and all these computers/devices we like so much. That means at least some of the old style calculations got it right. Change for the sake of change is just plain stupid.
Filip Dossche wrote:
If it ain't broke, don't fix it.
You have seen the educational levels of the average American right?
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In the U.S. we're currently suffering through "Common Core" teaching methods (I'll leave it to you to google "Common Core". Most of you remember the way we were taught to do subtraction:
32
-12
___
20This is the way Common Core teaches the same problem:
12 + 3 = 15
15 + 5 = 20
20 + 10 = 30
30 + 2 = 32
____
20I understand how they got there, but I DON'T understand how that's a better way to do it. :wtf: Maybe it's because a minus sign promotes negative thoughts about math...
".45 ACP - because shooting twice is just silly" - JSOP, 2010
-----
You can never have too much ammo - unless you're swimming, or on fire. - JSOP, 2010
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When you pry the gun from my cold dead hands, be careful - the barrel will be very hot. - JSOP, 2013I think the idea is to move from the lower number to the larger number in small steps that are each easy to do: 3 + 5 = 8, 8 + 10 = 18, 18 + 2 = 20 Yay! There is the answer! The old way way was obviously way too complicated where you have to do: The "ones" column: 2 - 2 = 0 The "tens" column: 3 - 1 = 2 ...and then you wrote the "tens" answer followed by the "ones" answer to get 20 Yay! There is the answer! Of course, you could make it even easier by only incrementing the lower number by 1 until you reached the larger number and then counting how many times you had to do that. 20 Yes! That should be the new method! Much simpler! Or, for future programmers using nice round, easily remembered numbers:
12 + 4 = 16
16 + 8 = 24
24 + 8 = 32
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20- I would love to change the world, but they won’t give me the source code.
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I'm in the US and luckily they are not doing that where I live.
There are only 10 types of people in the world, those who understand binary and those who don't.
It is determined largely by partisan political motivations. To keep it lounge-safe, I'll just say that where you are is a different political side than the national political side that is giving/taking money from local political bodies for accepting or rejecting this political agenda. There... I didn't argue about politics.
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In the U.S. we're currently suffering through "Common Core" teaching methods (I'll leave it to you to google "Common Core". Most of you remember the way we were taught to do subtraction:
32
-12
___
20This is the way Common Core teaches the same problem:
12 + 3 = 15
15 + 5 = 20
20 + 10 = 30
30 + 2 = 32
____
20I understand how they got there, but I DON'T understand how that's a better way to do it. :wtf: Maybe it's because a minus sign promotes negative thoughts about math...
".45 ACP - because shooting twice is just silly" - JSOP, 2010
-----
You can never have too much ammo - unless you're swimming, or on fire. - JSOP, 2010
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When you pry the gun from my cold dead hands, be careful - the barrel will be very hot. - JSOP, 2013My son's going through this now and it's driving my wife crazy. I've reviewed it and I think I understand the "why" behind it. I've started thinking I look at numbers differently than her. Most Americans learn math by memorization - flash cards, repetitive tables, etc. They don't think about what the numbers actually mean. They are stuck as they have only memorized base 10. What happens when you need to understand base 2, 8, 16, 535? The majority of Americans can't figure those out. They never had flash cards for that. However, this is teaching kids early how to understand the value of the number outside of what they have memorized.
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I think the idea is to move from the lower number to the larger number in small steps that are each easy to do: 3 + 5 = 8, 8 + 10 = 18, 18 + 2 = 20 Yay! There is the answer! The old way way was obviously way too complicated where you have to do: The "ones" column: 2 - 2 = 0 The "tens" column: 3 - 1 = 2 ...and then you wrote the "tens" answer followed by the "ones" answer to get 20 Yay! There is the answer! Of course, you could make it even easier by only incrementing the lower number by 1 until you reached the larger number and then counting how many times you had to do that. 20 Yes! That should be the new method! Much simpler! Or, for future programmers using nice round, easily remembered numbers:
12 + 4 = 16
16 + 8 = 24
24 + 8 = 32
____
20- I would love to change the world, but they won’t give me the source code.
Quote:
Of course, you could make it even easier by only incrementing the lower number by 1 until you reached the larger number
You can borrow my fingers if you need to. :)
There are only 10 types of people in the world, those who understand binary and those who don't.
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In the U.S. we're currently suffering through "Common Core" teaching methods (I'll leave it to you to google "Common Core". Most of you remember the way we were taught to do subtraction:
32
-12
___
20This is the way Common Core teaches the same problem:
12 + 3 = 15
15 + 5 = 20
20 + 10 = 30
30 + 2 = 32
____
20I understand how they got there, but I DON'T understand how that's a better way to do it. :wtf: Maybe it's because a minus sign promotes negative thoughts about math...
".45 ACP - because shooting twice is just silly" - JSOP, 2010
-----
You can never have too much ammo - unless you're swimming, or on fire. - JSOP, 2010
-----
When you pry the gun from my cold dead hands, be careful - the barrel will be very hot. - JSOP, 2013The more things change the more they stay the same. Some of you who have small children may have perhaps been put in the embarrassing position of being unable to do your child's arithmetic homework because of the current revolution in mathematics teaching...[^]
Did you ever see history portrayed as an old man with a wise brow and pulseless heart, waging all things in the balance of reason? Is not rather the genius of history like an eternal, imploring maiden, full of fire, with a burning heart and flaming soul, humanly warm and humanly beautiful? --Zachris Topelius Training a telescope on one’s own belly button will only reveal lint. You like that? You go right on staring at it. I prefer looking at galaxies. -- Sarah Hoyt
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You count up from 12 to 32, using easy incremental steps 12 + 3 = 15, then 15 + 5 = 20, etc util you get to 32. So it could be done shorter as well: 12 + 8 = 20 20 + 10 = 30 30 + 2 = 32 ------------ 8 + 10 + 2 = 20
How is that easier than the simpler way of just saying 32 - 20 = 12. Idiots.
"If you think it's expensive to hire a professional to do the job, wait until you hire an amateur." Red Adair. Those who seek perfection will only find imperfection nils illegitimus carborundum me, me, me me, in pictures
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In the U.S. we're currently suffering through "Common Core" teaching methods (I'll leave it to you to google "Common Core". Most of you remember the way we were taught to do subtraction:
32
-12
___
20This is the way Common Core teaches the same problem:
12 + 3 = 15
15 + 5 = 20
20 + 10 = 30
30 + 2 = 32
____
20I understand how they got there, but I DON'T understand how that's a better way to do it. :wtf: Maybe it's because a minus sign promotes negative thoughts about math...
".45 ACP - because shooting twice is just silly" - JSOP, 2010
-----
You can never have too much ammo - unless you're swimming, or on fire. - JSOP, 2010
-----
When you pry the gun from my cold dead hands, be careful - the barrel will be very hot. - JSOP, 2013Now I don't mean to defend this nonsense. Understanding how to subtract properly is clearly important and the 'count up in increments' method is generally longer and therefore more error prone. However, this is how people often count out change ("that's £6.52, sir" ... *hands over tenner* ... "and your change ... six fifty two, six sixty, seven, eight, ten" as he hands me the 8p, a 10p, two 20s, two £1s and a £2) and it may be a good way in for people who aren't getting it, or want a way to confirm their 'proper' subtraction is working correctly.
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It is almost as though they are deliberately enstupidising children.
--------------------------------- Obscurum per obscurius. Ad astra per alas porci. Quidquid latine dictum sit, altum videtur.
If we don't dumb our kids down who will work for and shop at Walmart?
Along with Antimatter and Dark Matter they've discovered the existence of Doesn't Matter which appears to have no effect on the universe whatsoever! Rich Tennant 5th Wave
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Now I don't mean to defend this nonsense. Understanding how to subtract properly is clearly important and the 'count up in increments' method is generally longer and therefore more error prone. However, this is how people often count out change ("that's £6.52, sir" ... *hands over tenner* ... "and your change ... six fifty two, six sixty, seven, eight, ten" as he hands me the 8p, a 10p, two 20s, two £1s and a £2) and it may be a good way in for people who aren't getting it, or want a way to confirm their 'proper' subtraction is working correctly.
That is well and good for counting UP in money, where you end on a larger denomination of base 10. But how will common core work on fractions and algebra/calculus, etc where you have to determine multiple variables, which may or may not be easily expressed as a base 10 whole number :omg:
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Quote:
It is almost as though they are deliberately enstupidising children.
Good thing you are already educated.
There are only 10 types of people in the world, those who understand binary and those who don't.
That's pronounced edumacated.
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In the U.S. we're currently suffering through "Common Core" teaching methods (I'll leave it to you to google "Common Core". Most of you remember the way we were taught to do subtraction:
32
-12
___
20This is the way Common Core teaches the same problem:
12 + 3 = 15
15 + 5 = 20
20 + 10 = 30
30 + 2 = 32
____
20I understand how they got there, but I DON'T understand how that's a better way to do it. :wtf: Maybe it's because a minus sign promotes negative thoughts about math...
".45 ACP - because shooting twice is just silly" - JSOP, 2010
-----
You can never have too much ammo - unless you're swimming, or on fire. - JSOP, 2010
-----
When you pry the gun from my cold dead hands, be careful - the barrel will be very hot. - JSOP, 2013It isn't a better way to do the calculation. It's a different way to teach the concepts about numbers. I assume there are other later lessons that focus on memorization. I learned using similar methods and beads back in the day. http://www.momentumlearning.ca/1/post/2012/03/counting-skip-counting-and-all-things-math.html[^]
Curvature of the Mind now with 3D
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That's pronounced edumacated.
Edumaciated?
You'll never get very far if all you do is follow instructions.
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In the U.S. we're currently suffering through "Common Core" teaching methods (I'll leave it to you to google "Common Core". Most of you remember the way we were taught to do subtraction:
32
-12
___
20This is the way Common Core teaches the same problem:
12 + 3 = 15
15 + 5 = 20
20 + 10 = 30
30 + 2 = 32
____
20I understand how they got there, but I DON'T understand how that's a better way to do it. :wtf: Maybe it's because a minus sign promotes negative thoughts about math...
".45 ACP - because shooting twice is just silly" - JSOP, 2010
-----
You can never have too much ammo - unless you're swimming, or on fire. - JSOP, 2010
-----
When you pry the gun from my cold dead hands, be careful - the barrel will be very hot. - JSOP, 2013I am not sure how this is better way. If someone claims this is helpful in real World calculations, I do not get how. I mean how can it be easy to subtract using 10 steps instead of traditional? If they are really after an alternate way, why not Vedic Maths[^]? I did a beginner course in middle school on it and did find it weird at first. But once I became habitual, it was quick. As far as this method is concerned, this[^] is what I found.
My CP workspace: Incredibly trivial and probably useless code samples[^]
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In the U.S. we're currently suffering through "Common Core" teaching methods (I'll leave it to you to google "Common Core". Most of you remember the way we were taught to do subtraction:
32
-12
___
20This is the way Common Core teaches the same problem:
12 + 3 = 15
15 + 5 = 20
20 + 10 = 30
30 + 2 = 32
____
20I understand how they got there, but I DON'T understand how that's a better way to do it. :wtf: Maybe it's because a minus sign promotes negative thoughts about math...
".45 ACP - because shooting twice is just silly" - JSOP, 2010
-----
You can never have too much ammo - unless you're swimming, or on fire. - JSOP, 2010
-----
When you pry the gun from my cold dead hands, be careful - the barrel will be very hot. - JSOP, 2013Now do
12
- 32
:cool: I think I saw that crap on one of my kid's math papers (7th grade) a while back. It's nonsense. We need to teach these kids 2s-complement -- it's the only true path!
You'll never get very far if all you do is follow instructions.
