[s]Common Core[/s] "NEW" Math Problem - Please Help Me Understand

[War Eagle!!!]

So what's the methodology here? Or did I miss that part of the thread where this was answered?

I don't think this is a real problem. I have no idea, but I haven't seen anything that looked like that before.

[Catphish Tilly]

I don't think this is a real problem. I have no idea, but I haven't seen anything that looked like that before.

Pppppf, I knew that. I was just testing to make sure you did. I'm sort of the WT of math and theorems and shit. Only more humble.

[WiregrassTiger]

It's interesting to read these differing opinions but shouldn't we defer to Chizad regarding this debate?

[Ogre]

I don't have a problem with them teaching what actual "subtraction" means and why 32-10=20.

Dadgum new math is changing everything!!!1

[The Six]

Yeah, so this was not a referendum on the good or bad of this type of math but a request to try and understand it.

A friend on the bookfaces replied with the following:

We actually already think the new way, but we either don't think about it or have forgotten. What we're doing is trying to get to "easy" math (multiples of 5 and 10).

Start at 12 then get to 15, 20, 30 and finally 32

3+5+10+2=20

Most of us have memorized the simple subtraction, but this is how our brains get there.

The best way to think about this is to consider giving or getting change back after a retail sale.

You buy something that costs $7.48, and pay with a $20 bill. What is the change?

7.48 + .02 = 7.50
7.50 + 2.50 = 10
10 + 10 = 20

10 + 2.50 + .02 = 12.52

Your change is $12.52

Subtraction, after all, is addition in reverse.

[Godfather]

Yeah, so this was not a referendum on the good or bad of this type of math but a request to try and understand it.

A friend on the bookfaces replied with the following:

Your friend might be a highly functioning retard.

[Saniflush]

Your friend might be a highly functioning retard.

I'm not sure about the high functioning part, but I am sure about the retard.

[Snaggletiger]

My phone has a calculator.

[Tiger Wench]

I have a high powered corporate job, so I don't ever need change from a $20.  Let the little people keep the difference.

[AUChizad]

So what's the methodology here? Or did I miss that part of the thread where this was answered?

First of all, I'm guessing TheSix saw this on facebook or some such shit followed by "Thanks Obama". I doubt sincerely that this is an actual homework problem.

Also, the first example:
 32
-12
___
20

That's not showing any methodology at all. That's just showing the problem and the answer. It's not showing that you start from the right and subtract 2-2 first and get zero, and since that's not a negative number, you don't have to cross out the three and put a little 2 above it, you can just subtract the 3-1, and get a 2. It's not showing how you arrived at 20, it's just assuming you memorized 32-12 is 20 just because it is. Contrarily, the "new math" example is going through and listing out all of the steps to get to the answer.

I don't have a strong opinion one way or another about it, but I get what they're demonstrating here.

Since math is a 10-based system, 5s and 10s are easier to count by. So they're saying to start from the number you're subtracting by (12), then get to the nearest 5 (15). If you're still not at the number you're subtracting from (32), then add another 5. Now you're at 20. An even 10 number. Still not to 32, so add another 10. Now you're at 30. Now if you add another 10 or 5, you've gone over the target number of 32, so just add the two. Then it's saying you can add all of the things you added and get the answer.

I'm not saying it's not convoluted or that there's anything wrong with the "old" system of math, but I get what they're doing.

And like Townhall already explained, it has nothing to do with Common Core.

[WiregrassTiger]

First of all, I'm guessing TheSix saw this on facebook or some such shoot followed by "Thanks Obama". I doubt sincerely that this is an actual homework problem.

Also, the first example:
 32
-12
___
20

That's not showing any methodology at all. That's just showing the problem and the answer. It's not showing that you start from the right and subtract 2-2 first and get zero, and since that's not a negative number, you don't have to cross out the three and put a little 2 above it, you can just subtract the 3-1, and get a 2. It's not showing how you arrived at 20, it's just assuming you memorized 32-12 is 20 just because it is. Contrarily, the "new math" example is going through and listing out all of the steps to get to the answer.

I don't have a strong opinion one way or another about it, but I get what they're demonstrating here.

Since math is a 10-based system, 5s and 10s are easier to count by. So they're saying to start from the number you're subtracting by (12), then get to the nearest 5 (15). If you're still not at the number you're subtracting from (32), then add another 5. Now you're at 20. An even 10 number. Still not to 32, so add another 10. Now you're at 30. Now if you add another 10 or 5, you've gone over the target number of 32, so just add the two. Then it's saying you can add all of the things you added and get the answer.

I'm not saying it's not convoluted or that there's anything wrong with the "old" system of math, but I get what they're doing.

And like Townhall already explained, it has nothing to do with Common Core.

You are damn good at counting by 10's. How high up can you go?

[GH2001]

First of all, I'm guessing TheSix saw this on facebook or some such shit followed by "Thanks Obama". I doubt sincerely that this is an actual homework problem.

Also, the first example:
 32
-12
___
20

That's not showing any methodology at all. That's just showing the problem and the answer. It's not showing that you start from the right and subtract 2-2 first and get zero, and since that's not a negative number, you don't have to cross out the three and put a little 2 above it, you can just subtract the 3-1, and get a 2. It's not showing how you arrived at 20, it's just assuming you memorized 32-12 is 20 just because it is. Contrarily, the "new math" example is going through and listing out all of the steps to get to the answer.

I don't have a strong opinion one way or another about it, but I get what they're demonstrating here.

Since math is a 10-based system, 5s and 10s are easier to count by. So they're saying to start from the number you're subtracting by (12), then get to the nearest 5 (15). If you're still not at the number you're subtracting from (32), then add another 5. Now you're at 20. An even 10 number. Still not to 32, so add another 10. Now you're at 30. Now if you add another 10 or 5, you've gone over the target number of 32, so just add the two. Then it's saying you can add all of the things you added and get the answer.

I'm not saying it's not convoluted or that there's anything wrong with the "old" system of math, but I get what they're doing.

And like Townhall already explained, it has nothing to do with Common Core.

wrong

wrong

wrong

All counts.

And yes, his friend is most def a tard.

[AUChizad]

wrong

You didn't post the original, so I don't think you're an authority on the authenticity of this homework assignment.

The fact that Buzz had a meme queued up disputing that it's common core is a huge tell to me that it's one of those many lobotomized facebook posts that drove me off of facebook.

wrong

How are they showing the methodology in the first example? Explain. How are you saying they're not in the second example? Explain.

wrong

Not sure if this one's for the explanation of the methodology they're using, which makes complete mathematical sense, or that it has nothing to do with Common Core. Either way, not wrong.

[Snaggletiger]

No Colonel Sanders, you're wrong.

[AUJarhead]

No Colonel Sanders, you're wrong.

Something's wrong with his medula oblongata!

[Tiger Wench]

First of all, I'm guessing TheSix saw this on facebook or some such shit followed by "Thanks Obama". I doubt sincerely that this is an actual homework problem.

Just worked through these with my son and second grade math this week.  The attached photo is not an example from his homework, but it is a representative sample of the stupid shit he has to do to prove he can subtract two numbers.  The old way is just fine - just work through it from right to left, and carry your ones if necessary!! This is just a scam to try and make new textbook money and have the new hip way of teaching math.  In this instance, the old way is the better way.

[Pell City Tiger]

What ever happened to the "KISS" method of problem solving?

[Token]

Just worked through these with my son and second grade math this week.  The attached photo is not an example from his homework, but it is a representative sample of the stupid shit he has to do to prove he can subtract two numbers.  The old way is just fine - just work through it from right to left, and carry your ones if necessary!! This is just a scam to try and make new textbook money and have the new hip way of teaching math.  In this instance, the old way is the better way.

I tried to explain this bullshit to smooth_operator. I can't believe how incredibly stupid this shit it. I just showed my 4th grader the "old" way to do it. It blew his mind how easy it was. His teacher didn't like it though. Just wait until you get to long division.

[Buzz Killington]

I tried to explain this bullshit to smooth_operator. I can't believe how incredibly stupid this shit it. I just showed my 4th grader the "old" way to do it. It blew his mind how easy it was. His teacher didn't like it though. Just wait until you get to long division.

^^This^^

[Tiger Wench]

I tried to explain this bullshit to smooth_operator. I can't believe how incredibly stupid this shit it. I just showed my 4th grader the "old" way to do it. It blew his mind how easy it was. His teacher didn't like it though. Just wait until you get to long division.

Child please - I have a fifth grader too!  This week was multiplying with decimals and I thought my engineer husband's skull was going to explode. I never claimed to be a math Jenius, and never will, but even I get the old method of "stacking" below the line and counting the places to the right of the decimal.

I guess we just have to remember that ALL math is obsolete now that our damn phones can figure shit for us with the touch of a "Siri" key.