I'm right, ain't I?
I'm right, ain't I?
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Borrow 1 from the 7 leaving you 10 and 6. This is what they tried to teach in schools for awhile but adults weren't getting it. Common Core? Is that what they called it?
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One of my wifes friends was an elemetry school teacher when common core was popular. We asked her what it was and as she was explaining it, i said, "oh, like how you do mental math?"
Im an engineer and i just assumed thats how everyone did math... apparently people just memorized everything
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Yeah, when I went through school they didn’t teach it this why but that is what I taught myself, much more simple math (+ & - with no * or ) in the same amount of steps.
Is that what they call Common Core? I’ve heard the term but didn’t know how it changed the method of teaching math.
Leave it to my AuDHD brain to figure out a less strenuous path to the same endpoint…
I wonder if this is an anxiety source for ASD/ADHD/AuDHD people. Having to constantly re-map lessons taught to fit my neurodivergent brain that it now feels like the entire neurotypical world is gaslighting neurodivergents.
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Just a heads up, your got absorbed by the text markdown Lemmy uses. You have to use a double slash to have it show up, like this
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Is that what they call Common Core? I’ve heard the term but didn’t know how it changed the method of teaching math.
Common core showed multiple ways that were intended to increase the understanding of how math works. This was one of the ways that was presented which wasn't how they taught it when I was a kid. There were at least two that I remember when my kiddo was doing common core:
- Double one of the numbers and add or subtract the difference between them (7 is two less than 9, so 9x9 then subtract 2)
- Take enough from the smaller number to reach 10 and add what is left (9+7 to 10+6)
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Why wouldn't you just take 1 from 7, add it to 9, and make it 10 + 6? That makes a lot more sense to my brain at least.
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He's a spider monkey with base 8 fingers.
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Because making shit equal, be in perfect balance or even symmetric makes my dopamine go 🥳.
Finding the correct answer that way is a neat side effect too.
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Multiplying by two is a similar cognitive exercise to adding 10 in small numbers (for me) so it would really depend on which occured to me first.
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Because that is the joke and why the teacher reacted that way.
Or translated into reddit: woosh
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This is all incorrect because 7 would inevitably cannibalize 9.
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That's why you instead take 1 from 7 and give to 9, making it 10+6
You can't allow the 8 into the same house as 7 and 9.
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9+anything
10+x-1Similarly for 8+x is 10+x-2
Multiplying by 5: mult by 10 divide by 2 Mult by 15: mult by 10, add half of that.
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Multiplying by 5: mult by 10 divide by 2
A very similar concept for tipping about 20% is taking 1/10th of the bill by moving the decimal one to the left and doubling that. To make it even easier for me I just round to the nearest $10 amount first.
Bill: $66.20 -> move left and round up = $7.00 and double to $14.00. The exact 20% amount is a little over $13 but I tend to round up because it is also faster to add whole dollars to the bill.
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I only read this thread to make sure someone was right. Thank you
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Heretic here. I just do 10 + 7 - 1.
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That's how I do it in my head too. Is this even uncommon?
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No many people have their own methods. I don't think this is exclusive to ADHD whatsoever
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That's okay.
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No take one from 7 and its 10+6=16
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Take 7 from 7 and its 16+0 =16
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Take 11 from 7 and it is 20-4=16
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This is how I think for sure.
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This way of thinking is just a different way of doing math and has absolutely nothing to do with ADHD. This type of post is likely responsible for a large portion of the people self diagnosing themselves with something that I struggle with.
Stop posting this shit.
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Same for like 60% of stuff on this community tbh
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I don't believe you have the numbers to back that claim up, misinformation spreader!
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Why wouldn't you take the 1 from the 7 so it is 10+6?
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This is what I go for...Just play in 10s. Alot easier IMO
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NOT LIKE THAT YOU HEATHEN
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not even ADHD related you're just taking a route to something more readily available in your memory. that's how brains are supposed to work.
to me the detour is -1+10. whenever i see a 9 i take 1 away from the other guy and then add 10.
9 x single digit mumber works similarly; except i take away 1 and complete that to 9 by adding a number next to it.
9x7 = ?
7-1 = 6
6+? = 9
9x7 = 63
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9x7 = 70 - 7 = 63 in table of 9 too easy ! (nearly the same technic)
8x7 = 70 - 7x2 = 70 - 14 = 6 + 70 - 20 = 56 (6 from 10-4 from 14)7x6 = 5x7 + 7 = 70/2 +7 = 35 + 7 = 42 the answer to the life, the death and all the rest (5xa = 10/2 x a= 10a/2)
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i mentioned the 5x trick elsewhere under this post but for me for some reason doing the halfing first is easier. so to me it's a/2x10 instead.
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You’re so adhd you forgot that this was a whole part of your math curriculum that you just tuned out because you already knew it.
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More likely this is a person who was at school pre-2011 when common core was implemented.
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My maths teachers encouraged that kinda calculations tbh... Makes sense why I like maths
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It's basically "common core" math (in the US), or just "updated curriculum" everywhere else in the world. Turns out that building fluency with math through play and number decomposition is incredibly powerful for long-term learning.
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I thought you give 1 from 7 to 9 so it becomes 10+6 !!
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You can do that, too.
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Said by someone who never actually told that to a teacher, lol.
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OPs description is literally the simplest example of the dreaded "new math" they are teaching in schools.
9+7 is the same as 9+1+6 is the same as 10+6 is 16. New math. Same as the old math.
ETA: one of the points of "new math", iirc, is essentially to teach all kids to use the methods that the kids who are "naturally gifted" at arithmetic sort of figured out on their own. So, congrats?
It's less about "changing the way we do math" and more about "teaching kids to break down problems to their simplest elements"...which is an all-around important life skill, aside from just math.
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A very good song by Tom Lehrer as well.
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For the last fifteen years, the emphasis in math teaching is that all methods to the right answer are correct. Emphasis is on sharing all the different methods. (Canada)
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That is what Common Core in the US was attempting to do, show several approaches including the one in the OP to help understand how match works instead of teaching the 'one true way' that was common prior.
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This is actually how my professor, who has a PhD in mathematics, does math.
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This is literally how common core math works.
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I do it like 7-1=6 and 9+1=10 and 10+6=16
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This is encouraged in 'new math'! Kids are explicitly taught and validated in using these compensation strategies instead of feeling like they are doing something wrong.
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Well that would have helped me back in the 2000's when i was told i worked out maths problems differently to everyone else with this sort of method even though i got the same answers. One teacher had me show my working out for a bunch of problems to understand how i was doing it and it made me internally feel bad at maths because i did it 'wrong'.
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The answer is 69
420% of the time.-
Niiiiice
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9+9-2
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Just as acceptable
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I mean, sure, the choice of the "nice" numbers here is eccentric, but this is essentially the way math is taught nowadays. Only, instead of making 8 in this special case, the goal is usually to make 10 + leftovers because adding to 10 is always easy.
Here's my (upper midwest) spicy mental math take: it should be big-endian and solved with backtracking for ripple carry/borrow. None of this starting-from-the-1's-place-and-successively-incorporating-higher-order-digits nonsense. Extended carry/borrow is rare, and if you start with the most significant digits and give up/get bored part way through, the intermediate answer is in the ballpark of the real answer.
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And here I always thought it was 1001 + 0111 = 10000.
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A dozen years ago or so there was a huge uproar about "common core" mathematics, which was a new standard being used in the USA for teaching.
It was a politicized trendy topic and even so-called-intellectuals were jumping on the train and calling it a deranged way of learning math.
I looked into it a bit, and I swear this pic pretty much sums up one of the key methods they were teaching.
Basically just tricks that a lot of people figure out to simplify problems.
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That's exactly what it is. A way to help conceptualize and play with numbers. Stuff my bored ass was doing in school anyway before common core came around lol
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Common core is still a thing. I wish I had common core as a kid. Makes way more sense.
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I've always done it this way and don't have adhd
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Ok but this is actual a very useful way of thinking about algebra problems. Much easier to add large numbers in your head or solve simple equations if you get practiced at this
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My removed ass: 9 is 0b1001 and 7 is 0b111, 0b1001+0b111 is 0b10000 which is 16.
Am kidding, I take 9's ten friend, sub-stract that from 7 et voilà I have 6 ones and 1 ten which is 16.
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This is psychopathy. Clearly you just add the 1 to the 9 to make it 10 and subtract it from the 7 to get 6 and 10+6 = 16.
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Holy shit.
Is that not how “normal” people do math in their head? How do they do it?
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I have no idea how normal people do it but I do
9+7
One shy of 10+7
One shy of 17
16
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How do they do it?
I assume they just don't. For my mom at least, she absolutely will not apply mental effort to anything that doesn't strictly require it. If a mental task can be offloaded to someone or something else, she'll do that instead, every time.
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Your teachers are bad at their job. There is nothing wrong with that method. Now, if you also try to do 7+3 as 5+5, you might need to learn other method so next time, you choose a more efficient one. But against that would not be wrong.
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Especially since the thrust of the new math curriculum seems to be more about being nimble with numbers and being able to conceptualize and compartmentalize their values rather than learning rote formula.
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9 is one less than 10, and 7 is three less than 10, so combined, they're four less than 20 = 16
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I used to work at a gas station, and I was always giving different amounts of change, and so I accidentally memorized every single possible combination of digits and coins from 1 to 99.
I no longer have to think, I have a lookup table.
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You made a change rainbow table!!! Love it!
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The legend said that it is how Gaussian elimination was discovered in europe
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That’s the most logical way! They are the heathens!
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Is this engagement bait to get all the people who do it differently because it worked lol
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10 + 7 = 17 17- 1 = 16
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Me: so 9 is 10-1 so you can do 10+7=17 and take away one so 16
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I think this is precisely how math is taught through Common Core now.
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Idk I have adhd and my working memory is so poor that memorizing time tables was the only way. :/
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As long as your method gives you the correct answer, I see no need to correct anyone.
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lol yep, precisely
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Actually, no. One of the core goals of the US Common Core math standards is to make explicit this type of compensation strategy. One of the main ones emphasized for addition/subtraction is 'taking from/completing a ten' but there is a lot of work to help kids internalize these kinds of doubles strategies!
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Ever think that maybe this person was schooled befor 2011 when common core math was implemented?
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Doesn't matter. The meme specifies 'someone, usually a teacher' scolding them. If the teacher is teaching math since 2011 (i.e. today) they should recognize and encourage this strategy.
Please improve your reading comprehension before trying to be a smug scold.
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AI does this like someone having ADHD while on meth.
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Just wait until you find out what people with ADHD are prescribed
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For whatever reasons numbers fall out of my short term memory and odd numbers even moreso.
That's the sort of thing "new math" was trying to teach. Those sorts of breakdowns are exactly what the kids who were good at math were always doing, and teaching methods eventually caught up and realized they should just teach the tricks.
Then a bunch of parents who were bad at math asked "new math? How can math change?" The fact that they even asked that question showed how their math education was lacking, but they seem to have won.
Exactly. Math has historically relied on rote memory for most mental math. Kids would have to fill out their times tables, addition tables, etc until they memorized them. I still remember getting pop quizzes in elementary school that looked like this:
You only had two minutes to fill out the entire thing, which meant you only had 1.2 seconds per answer. You didn’t have time to actually calculate them. The point was that you were expected to have them memorized ahead of time instead of calculating each one.
But rote memory is laughably bad at actually teaching concepts. You may know that 12x5 is 60, but you don’t have any understanding on why, or other ways to do that same calculation without rote memory. And rote memory is only decently reliable up to ~12x12. Anything past that, and it becomes too much info to track; kids simply start forgetting answers.
The kids who were good at math (and I mean actually good at math, not just good at memorizing things) quickly devised methods to do this shit in our heads easily. Keeping track of multiple numbers in your head gets confusing. So “line them all up, add straight down, and carry 1’s” sort of falls apart if you’re doing it in your head. Especially if you’re trying to keep track of more than three or four numbers at a time.
Essentially, 127+248+30 is the same as 105+250+50, but the latter is much easier to parse in your head. But yeah, the parents (who primarily relied on rote memory) didn’t understand why the new method would be more effective, because they didn’t understand the concepts surrounding the math.
I think it's good to have a good set of these tables memorized and then based off those you can bounce your tricks. Eg if you know 5x12 by heart, you get 5x24 by intuition. Or even if you know 24/2 for that matter. I use simple examples but this could scale to less memorable numbers too.
Strongly disagree that memorization isn't important. It's THE foundation to be able to do effectively do more advanced stuff.
Take the equation (5678 • 9876). Use long multiplication and you only rely on doing a bunch of single digit multiplications and additions. It's so much faster to be able to instantly know each step instead of having to recalculate these "atomic" steps again and again in your head.
You generally don't need to be able to solve multiplications involving double digits in your head. It's nice-to-have but otherwise useless, as long as you're able to calculate the ballpark of the result.
For example, (38•63) is roughly 2400 and I can then calculate it on paper instead of in my head.
Head calculations are just so much more error-prone than written calculations. Don't do them if you can avoid them. There's a reason why math students (at a university) are infamous for being unable to make the simplest calculations in their head. It takes effort that could be spent somewhere else.
i used to hate the times table but i definitely think it's essential to mental math. even if you vaguely remember it it will help. like knowing 42 shows up somewhere in the 7x and 6x may help you remember 6x7. or if you remember a neighbor you can just add or subtract the number once. for example if you don't remember 7x6 it definitely helps to know each neighbor (both of which are easier to me since one is a 5x and one is a square number)... so either you think about 7x5 which is 35 so you can add another 7 to it or 6x6 which is 36 so you can add another 6 to it.
I only sort of agree. I still think that by forcing you to do that, by making you practice, makes the calculations "muscle memory" in that you aren't memorizing the answers but can do the calculations faster and faster each time.
Sure. Some people could memorize them. But others will learn to calculate quickly.
I was trying to explain how and why they were teaching math to a family friend and they didn't get it(multiplication stuff). I broke it down with pen and paper and they didn't get it. Simpler example, nope. Eventually I had to explain how multiplication is just repetitive addition. They responded with WHAT! and I realized why they always wore open toed shoes. I sent them a link for 5th graders.
Hey! Nothing wrong with open toed shoes damnit.
I'm not very good at math (but not an idiot like your example) and I wear flip-flops every day of the year but they're not related.
Are you trying to say something like "too dumb to tie shoelaces?"
Because there are quite a lot of lace-up open toe shoes and sandals, as well as closed toe shoes without laces, so that doesn't track.
As a parent who is bad at math, you’re not wrong. But given my kids are excelling in math (very high scores), I’ve learned to shut the fuck up about it and let the teachers do their
black magicjobs.I want to add that when I said they give away that their arguments demonstrate why math education needed to change, I do mean it. This is a clear cut case of the education system failing them.
I'd normally be happy to throw snark at the idiot things parents say that make our education system worse, but not this time.
Well... kinda. "Getting to 10" was what New Math was trying to teach. So you'd take the 1 from 7 and give to 9, because 6 + 10 is easier than trying to finagle your way to 8x2.
You don't have to be bad at math, strictly speaking. But there was a lot of brute memorization in traditional math. Times Tables, for instance, were something you just memorized straight up without thinking too deeply. Getting 16 out of 7+9 was something you just had to do on your fingers until you had it lodged in your head.
Old Math tended to be slower and more tedious. New Math is more logical, but also somewhat counterintuitive until you get into the swing of it.
I've got friends with kids down in Houston. "New Math" appears to be alive and well, in no small part because it helps kids score higher on standardized tests.
Never heard about new math. Where does this method comes from (geographically)?
The deep past https://en.m.wikipedia.org/wiki/New_Math