I mean, the answer is he subtracted 306 instead of 316. Presumably they wanted one additional arch with a value of 10 between the big ones and the small ones. It's not hard to figure out. But it is stupidly over complicated.
@JJJSchmidt, Even reading your comment I don't understand how they wanted this solved and I'm working on getting a manufacturing degree. Why is there even a number line for subtraction? Just use a calculator.
@ShinyMegaMetagross, It seems like they want you to demonstrate the physical process of subtraction. As in show the value moving incrementally down the number line as you reduce it by 300 then 10 then 6.
@JJJSchmidt, Alright that makes more sense. I mean it still looks stupid when you could just teach the kid 7-6=1, 2-1=1, 4-3=1 so the answer is 111 but I think I get what they wanted.
@JJJSchmidt, This is the only part of common core that I understand what they are trying to do. This method isn't meant to be the quickest way to get the answer, in fact the answer isn't all that important. They are trying to teach how the numbers can be broken down into base numbers. The method isn't really that far off how the mother wrote it down. You have 427 written over the subtracting number 316. When subtracting a large number, you first the 6 from the seven, then the 1 from the 2 and finally 3 from 4. The difference is that this is showing it done on a number line in which they do it in the opposite order.
@JJJSchmidt, As someone who has always been fascinated by numbering systems, this idea is not complicated. Just different. Our numbering system revolves around 10s. This particular example is easy to subtract the standard way without anything carrying over, 4-3, 2-1, 7-6. However, an example like 312-178 is a little different. Using common core you would break this down into 3 steps. Since 178 in our numbering system is 100 + 70 + 8, you can solve easily by doing 312-100 (212), then -70 (142), then -8 for a final result of 134. Or, you can also add whatever value you want to both numbers for easy math, say 22, to get the subtracted number to a multiple of 100 (334-200=134). Just use whatever method works the best for the particular problem for you.
@Lord Solmyr, Can also take each number to the nearest 10 (300-170=130), then subtract the remainders (12-8=4) for the same result :)
The idea behind common core math is to get students to use numbers that end in either 5 or 0 because they are easier to use. Like 32-12 is solved by adding 3 to 12 then 5, 10, and then 2. So 3+5+10+2=20. But why not do 8+12 to get the answer of 20? BECAUSE THATS WRONG! Plus politicians can't do that complex of math. They don't have 12 fingers.
@Coozination, Wait... So common core wants people to learn to subtract by using addition?
@Coozination, The politicians part is hilarious because I learned in Political Science (and thus can't confirm, forgive me if I'm wrong) that common core was designed by experienced educators, then fvcked up by politicians.
@ShinyMegaMetagross, Common Core wants students to understand the concepts behind math, not just rote memorization of formulas.
@SimonPetrikov, that's exactly right. Also, there was an attempt at nationalized standards in the 90s but they started with history, so, uh, you can imagine how well that worked out...
@ShinyMegaMetagross, short version, yes. The whole 3-1=2; 2-2=0; answer is 20 version is not being taught. What it comes down to is they want you to write out the shortcuts we use when we do math in our heads (ex moving the decimal to take 10% of a number) Which is why I say if you wanna teach it that way fvck 3+5+10+2, do 8+12.
And just for the record for those who don't believe me, my undergrad degree is in teaching.
I am so confused
No wonder why this parent is frustrated. They're not very good at seeing patterns and figuring things out. These are critical for engineers. Got some bad news for you if you can only do something one way any have trouble with a number line.
Starting with 427 you subtract 3 100s giving you 127.
Then you go to the tens place and subtract 1 giving you 117.
Then to the ones place where you subtract 6 giving you 111.
Parent failed to follow the prompt. Got the right answer but used knowledge the kids likely had yet to see.
They are the same method, just the parent has learned a trick that they soon will learn but if you just teach students tricks they won't understand what is actually going on. Understanding is crucial.
@mas2de, finally, someone who actually gets it
@mas2de, as someone with a masters in mathematics I'm going to have to disagree with you. I was doing basic algebra by the time I was 8 and this took me longer to figure out then the REGULAR mathematics way. It takes longer and is more complicated then it is to actually subtract one from another.
@RiffRaff, because we've learned all this so long ago that we had to re-figure it out. Took me a second too. Once we know the basis, we can learn the tricks. Then all we need, use and really remember is the tricks and would have to try to remember the basics of it.
@RiffRaff, I'm pretty sure this isn't even common core. I remember doing stuff like this as a kid when I was first learning math. Born '89.
Common core math is absolutely retarded and a great example of breaking something as a direct result of trying to fix what wasn't broken.
@I Are Lebo, The problem with Common Core was its poor implementation. The actual concept of Common Core is good. It's just about teaching kids math concepts rather then making them memorize formulas. Common Core wants students to know why you subtract, or divide, or whatever, and it wants students to know multiple ways of solving the same problem because learning is not one size fits all. The goal of Common Core is a deeper conceptual understanding. There's nothing at all wrong with that. I say this as a teacher, don't you want kids to be taught how to think instead of memorize?
@Ruupasya, yes. But this teaches them to think in impractical ways. There's a middle ground between rote memorization and common core, and that middle ground is what I got while growing up. I can't remember many of the post trigonometry formulas, because I was never given context for them. The real problem is 'word problems'. Every math problem should be a word problem because context is what matters the most.
Schools need to teach kids how to do taxes and how to balance a check book. This needs to be in core mathematics. Students stop paying attention and stop learning because they realize (accurately in most cases) will never be useful to them and won't have any real world applications.
Common core is making the problem worse, not better.
@I Are Lebo, having said that, the way I was taught BEDMAS worked great. I have zero issues with addition subtraction, multiplication, division, or with exponents.
This is because I was taught how the numbers relate to each other. I wasn't made to memorize tables, nor was I taught how to think. I was shown a problem, and helped to find my own best way of solving it.
@I Are Lebo, "I was shown a problem, and helped to find my own best way of solving it" is exactly what I meant by teaching students to think.
@Ruupasya, yes, but this way of doing math is unintuitive.
@I Are Lebo, I disagree, it's how I've always done math in my head without being taught. What's 587 minus 422? Well 500-400 is 100, then we have 87-22, uh, 80-20 is 60 so we've got 16?, 7-2 works and is 5, so 165. Or i might do 422-22 = 400, 587-400 = 187-22 = 165
@Ruupasya, I do it backwards.
7-2=5, 80-20=60, 500-400=100
Maybe the problem is explaining it. Common core is usually explained so inefficiently, it becomes an indecipherable mess.
@Ruupasya, however, the way I've seen it with common core is outright retarded.
The idea of taking that same problem and making it a mix of rounding and addition to solve a subtraction problem is unintuitive, confusing, inefficient, and complex enough that you won't get the lesson through to most people.
Confused students aren't learning anything.
My daughter is learning under common core. This isn't anything I've seen. This looks like another fake assignment the mouth breathers in the anti-common core groups cooked up to fearmonger. Listen, common core is a set of standards to teach kids why the answer is the answer, and THEN we teach them the old school ways of using the shorter steps to get to the answer. Educators are sick of seeing kids being only taught memorization without knowing what to actually fvcking do regarding math. We are WAY behind in this country concerning maths and sciences compared to the globe. It's quite embarrassing. Common Core is the best solutions. The fact that my 4th grade, 8yo daughter could literally take the prealgebra college course I'm taking and pass it speaks volumes into how the standards are working.
@Pizzazz, also, it teaches kids that they can use their own method of solving equations that makes most sense to them as long as they understand and reach the correct answer. Not everyone understands the same way to solve. We aren't robots. That's why they're teaching more methods of solving.
@Pizzazz, someone with one braincell down voted you twice
@Pizzazz, pre-algebra is for scrubs.
@Pizzazz, we'll i mean I never learned common core and am fully capable of solving things different ways just from common sense. if less people blamed cariculum and figured it out for themselves then we wouldn't be so far behind. truthfully we waste more time coming up with all these new ways to teach the same exact thing that there's no time for the important stuff. not saying it's all bad but I don't see a reason to come in here all harsh about it either. I don't see how this method is better than the old personally, granted this ones a poor example because the idea would be to use it on something that appears more difficult like 413-186. it's really just stretched out grouping. no different than saying 13-6 is 7 and 407-180 is 327. I agree with the mom in this imo. looks like a waste of time.
@Caine, the real issue is that people are lazy and want the teacher to show them literally everything rather than applying their own effort at home.
@Caine, my dad is a public school teacher and you're completely right. People want teachers to magically transform their kids into well behaved geniuses, and it's just not possible.
It's the same thing with discipline. Every year the school boards take away more and more authority from teachers, then don't understand why discipline is low.
Did you know that if a seven year old student stabs a teacher in the leg and that teacher smacks them away in defence, that teacher will get fired? It's ridiculous. I'm not advocating for bringing back corporal punishment in school, but teachers nowadays have zero real authority.
@Caine, if you read what I said, I addressed this as something I've never seen in my daughter's homework. There was a huge movement, now seems to have died out, against common core and they were making fake pics like this to scare people. Humanity will always fear change and do anything to stop it, even if it's for our benefit. It's really pathetic most days.
@the fork, for 4th graders, it's actually quite awesome to see them understanding it. I'm the product of old school math education, therefore, I could never properly understand it and gave up trying. I've actually been applying her Common Core solving methods to my homework and it's starting to click for me.
@Pizzazz, I'm a teacher, and I've seen something similar to this before. It's just basically
500 + 80 + 7
- 400 + 70 + 6
100 + 10 + 1 = 111
(i made up the numbers so i didn't have to keep switching back to the main pic)
@Pizzazz, I was kidding, but virtually all of us are a product of old school math education, everyone just has different strengths and weaknesses. I'd say you have an exceptionally smart daughter.
My beef with common core is how ridiculously complicated it can be. When the student, the teacher aide, the teacher, and even another teacher from another class are all scratvhjng their heads at the process, there's something wrong.
@TheKen42, there not doing it right, then.
Honestly, common core isn't THAT bad. There are a few problems, one being the standards set. It makes teachers move fast to try to cover everything (which is always an issue). Second, parents don't know it. If you are going to change something like how to solve a math problem, send a sheet home with the kids, or a video link. Something to help the parents so they can help the child with homework. It is nice for kids to be taught many ways to do a problem and allow them to pick what they like, but there isn't normally enough time to teach all the ways to do a problem.....
@EdiblePaper, exactly. back in our generation it was assumed that we would pursue it on our own time.
It was just one issue i had a problem with. There are alot of things i disagree with besides my key scenario.
Thank the gods I'm out of school!
So surprisingly that the government can't make up it's mind / figure out how to teach.
@Dephenistrator, this is way better than every state having a completely different set of standards. what happens to kids who move around a lot? they become completely lost.
@Ruupasya, even at it's best the school system is broken and garbage.
@Dephenistrator, oh, i agree with you there. I'm a teacher, and i think that the way the school system works is highly outdated and needs to be entirely revamped from the ground up. Like, for instance, why do we group kids by age instead of skill level? But there are a lot of things that certain schools are doing that i hope catch on, like modular scheduling and personalized learning.
@Ruupasya, modular scheduling was something i argued in my high school senior essay of "what's wrong with school and why" i was pissed that year because i was held back from graduation since they altered my computer science credit from science to a business credit and didn't meet requirements. My counselor never even brought it up until it was too late. I made an essay on what i thought was wrong and tacked 100 copies of it over school during the senior prank week. Still mad about that actually
@Dephenistrator, modular scheduling is basically just college-like scheduling. What's wrong with your scenario is that they change the credit type without informing you or grandfathering you in.
@Ruupasya, i understand the difference, modular scheduling just isn't the only problem i have with shool systems.