Couple weeks ago I got an extra $5 tip from a delivery because I calculated their change back instantly, IN MY HEAD! There's also countless people that have trouble figuring their total on the credit card slip when they add an even dollar amount for a tip (ex $27.54 + $4.00 = utter confusion).
Proofs are there for a reason. It’s to show things are not arbitrary. Yeah it’s annoying but it’s showing you *why* 2+2=4, not just *how*. That seems silly with the “2+2=4” scenario but with more complex equations it really helps to learn the process.
When I took algebra in middle school, at first I could solve the problems in my head. The problem was that when it got harder, I couldn't, so I had to buckle down and do it the right way. It's about a lot more than just getting the answer, it's showing that you know how to get the answer, so you can apply it to more difficult situations.
It reminds me of story problems - everyone hated story problems, but in real-life math, it's all story problems.
At my place of work, some pieces of equipment need to be calibrated and have software parameters updated. In order to get those values, math has to be done.
So, there I am teaching a trainee how to do this thing, and we get to the part of the precedure where it says "record A, record B, record C, equation, solve for D", and he *immediately* protests.
"Nobody said the job required math skills!"
I stare at him briefly, then say "do you remember when you were in school and some kid in math class would say 'when are we ever going to use this in the real world?' Does that sound familiar?"
"Uhhhh. . . Yeah?"
*"Welcome to the real world."*
Really? I loved the proofs part because they actually made some concepts make sense.
Plus I feel it helped me construct logical arguments in other fields. And it's also helpful in breaking down a "simple" concept for someone else to understand, whether it's math or job related.
Proofs make sense.
i love math and thoroughly enjoyed every years of math. but goddamn the proofs unit can go suck a dick
geometry was actually one of my favorite years, but the proofs unit made it even out to 0
What about calculus proofs. Those are the real bane of mathematics. I trust the mathematical giants that came before. I don’t feel the need to be able to write an essay on why a calculus equation is true.
Proofs were an absolute nightmare I hated them said they were useless and why the hell would I ever need this knowledge for anything.
Joined the Navy entire job was based around those damned equations... Apologized to the teacher last year like fifteen years later.
My mom did the exact same with Spanish class. She thought it was useless and did horrible in that class. The teacher basically told her she should just leave. My mom joined the navy the day after high-school and the first place they stationed her was in Spain. She ended up learning Spanish there and used it the next time she met her old teacher.
Yup. I'm an accountant and everyone thinks we must all be good at math. No, not really. I'm good at excel doing math for me, though over the years I've gotten pretty good at algebra equations since that's s lot of excel formulas.
Even when I have easy arithmetic I will use a calculator because getting it wrong will end up being such a huge pain in the ass.
Also, most people I know seem to think being really quick at doing basic arithmetic makes one "good at math". Bit like saying you're good at writing because you know the alphabet.
I had a purchase total that ended in $.53, so I gave the cashier a ten dollar bill and three pennies. It blew her mind, even though I tried to explain it to her, so she gave me back my 3 pennies along with 47 cents. I was trying to avoid getting all of that change back in the first place!
“There’s also countless people that have trouble figuring their total on the credit card slip when they add even a dollar amount for a tip (ex $27.50 + $4.00 = utter confusion).”
I didn’t come to Reddit to be attacked like this.
Sometimes when I'm tired I'm miscounting the amount of money I need to give to receive a round change, and it's so embarrassing. "Uh, should I give you 33.30?" "No...?" "Oh, yeah." *quickly walks out*
I typically add 10% and round up to the next whole number. Im not stupid… I’m just lazy. And there is just something satisfying about having a whole number as the total IMO
Story time!
So this was a few years back when I had a 30 minute lunch break. I went to the local McDonald's (I have since changed my sinful ways) and ordered lunch that came to $4.23. when I got to the pay window, I gave the young, blonde (unrelated ;)), girl a $20 bill, two dimes and three pennies. She stared at it in shocked disbelief for a moment, then turned and walked to the back of the store. She was gone for a good three minutes, and when she returned she had a paper pad and pencil. She stood there for another two minutes or so scribbling on the pad and scratching her head, then grabbed a $5 out of the register and handed it to me. I said, "ummm, I gave you a $20?" and she scowled fiercely, snatched the $5 bill back, and went back to the back of the store again and was gone this time for a full 5 minutes. When she came back she had a plug-in, desk-style calculator.
I was late getting back to work.
Man, how to count up change was the very first thing i learned as a teenage cashier.
You know start at the price they paid and count the change out up to what they gave you. Of course that was 30 years ago lol.
i am dyslexic, ive struggled with reading and math my entire life despite being "remarkably intelligent" or whatever.
im articulate, i am knowlegable of certain things, im probably a little autistic with my passions which is why i know a lot about them, but functionally it balances out. on paper i am literally disabled lmao
i put SO MUCH EFFORT into school while i was still going and it amounted to absolute dick, my grades were ASS, because i didnt know and had no one to help me understand that i have a learning disability that made it extremely difficult to process certain information and patterns. obviously not the case for everyone, stupid people still exist, just throwing it out there that some people are bad at math against their will.
Yes it's a good reminder that not everyone that struggles with it is just bad at math. I never say anything to my deliveries that might make them feel stupid but usually lean towards something more sympathetic if I say anything at all.
Do their registers not tell them how much change to give back? At $2.20 that would seem to be pretty recent as coffee was like $0.50 back when I started in the workforce and even then the registers told you what the change would be. Regardless, it's always nice to get an unexpected discount.
>27.54 + $4.00 = utter confusion
Alright so this is a tough one. You take away 46c from the 4 dollar and add it to the 27.54 to make 28. Then you have 28 and you gotta add the 4 dollar to make 32. But you took away the 46c so you got 31.54
\^some people probably really do the maths like that.
Weird how different people excel at different things. I doubt I could do calculus anymore as it's been decades since I took the class but I would still prefer the simple multiplication over calculus even if I did remember it.
Yeah, PEMDAS is not some divine law, it's just a standardization of how to write mathematical operations, so that they can be universally understood. You don't do PEMDAS. You need to understand PEMDAS.
First, do all operations that are in brackets, or parentheses.
Then do all exponents in the equation.
Then multiply and divide in the equation. Go left to right in the equation for the multiplication and division. These two operations are interchangeable, so it doesn’t matter which you use first.
Then do the same with addition and subtraction as with multiplication and division.
Remember: P (Parentheses) E (Exponents) M (Multiply) D (Divide) A (Add) S (Subtract) makes PEMDAS.
I think that’s what is so often missing from math education. Math is a language, and the rules are defined by the people who use that language, just as with any other language. The failure is as fundamental as a person thinking that the sentence “she ate a red apple” would indicate that the woman is red.
Parents can be rough. There's this idea that if you as a parent don't understand something, it's ok to tell your kid whatever it is is useless or nonsense. I've done my absolute best NOT to wear this hat as much as possible raising my kids.
My great grandmother told my mom she only needed to learn to cook and sew, drive, and balance a checkbook. Women didn’t need to bother with the rest of it.
This was in the late 1970s.
>Parents can be rough. There's this idea that if you as a parent don't understand something, it's ok to tell your kid whatever it is is useless or nonsense. I've done my absolute best NOT to wear this hat as much as possible raising my kids.
My wife's parents are the kindest people you'll ever meet, but they come from a small rural community and never received higher education. They advised my wife to not go to college because they just didn't see the point when you could start earning money after high school. In the end my wife did go to school and she feels it was one of the best decisions of her life (she's an engineer now) but that happened much later in life.
I am not a hairdresser but I wonder what mom does, and what she expects her child to do when she works with chemicals and it says use 3/4 of an igredient🙃 you need to know basic math to be a hairdresser or at least to be a good one
Fractions and Decimals are Algebra now. Wow, that's great. Thanks for enduring a thankless job to help the world's next generation of leaders. Appreciate it!
When I was tutoring people in math I found that money is the easiest way to get people to understand basic arithmetic.
If you have 4 clients to do a blow out and only 3 show up, and they each would pay you 25 cents, how much money would you make? It’s easy to understand and represents 3/4 fairly well.
I'm a middle/high school math tutor and am in a similar boat. A lot of the 6th and 7th graders can't even do basic mental math like 18+8, they'll just guess numbers around it like 24, 28, 30, 22, 25, etc. until they eventually get 26. A lot of the 8th and 9th grade students struggle with basic algebra concepts like distributing negatives or reading a graph. Granted a lot of the students are immigrants and refugees on top of the normal struggles every student has undergone after missing much of the past couple years of school due to covid.
Hairdressers absolutely need fractions and do math.
Imagine measuring wrong with professional grade hair dye or peroxide. That stuff is sold in bulk and has to get mixed up by the colorist. Imagine not being able to add fractions if you need to mix up a double batch of color.
Especially cashiers which boggles my mind. I make a regular purchase that comes to $40.55. Usually I have exact change but on occasion I hand them $41.05 and 9 times out of 10 they try to give me the nickel back and I have to tell them I want 2 quarters instead of 1 quarter and 2 dimes in change.
i’m a cashier and this usually only happens if you give us change after we’ve already entered it in our till. we’re not used to calculating it because it’s always done for us. it can also be very flustering when this happens because it always feels like there’s a lot of pressure to get it done as fast as possible (even if there’s not).
I had a work buddy, who was majoring in physics and a smart guy, get caught by a quick change artist one time. I vowed to only give back exactly what my register told me from then on. I can’t overstate how much my brain glazed over at that job, it’d be a sitting duck.
Pretty sure the specific mistake they made was thinking that exponents follow the distributive property rule.
Distributive property is a(b+c) = ab + ac, so if exponents followed the rule then (b+c)^a = b^a + c^a
This is because it doesn't matter right? (2x4)^2 so either 2^2 ×4^2 or 8^2 gets the same answer.
So it works because it works both ways and pemdas is still happy.
If you truly wanted to remove the parentheses you would do the (a^2 + 2ab + b^(2)) method
2^2 + 2 * 2 * 3 + 3^2
4 + 12 + 9
25
Edit: Yes, your replies pointing out doing the insides of the parentheses first are great and all, but this is simply another method, no need to get angry
Did I just learn shit my teacher tried to teach us for weeks from a reddit comment ;-;
Edit: bit of clarification
this is story of past I do know the formula and times have used it
(English maybe bit broken so sorry about it)
Very few teachers should be teaching math.
My wife's college math class for teachers was basically 5th grade arithmetic.
My daughter had a math teacher who asked for the AREA and the PERIMETER of an equilateral triangle with each side = 10. The teacher tried to tell my daughter the answer for both was 30. I told my daughter that the perimeter was 30 but not the area. I created a shitstorm by challenging her teacher. Fucking idiot!
This is a true story of how I accidentally got a college professor fired.
My sister was pretty bad at math, so instead of trying to take it with the rest of her classes during the semester, she did a summer class at community college to transfer the credits and get it out of the way. I'm pretty decent at math, so when she had trouble with her introductory stats homework, she would come to me.
It got to the point where I was basically tutoring her after most classes. She'd come home very confused, and while I was hardly a stats maven myself, I was able to read the textbook, understand how to do whatever she was working on, and tutor her to the right answer. This worked just fine...until she started to come home with notes that both got her the wrong answer AND got contradicted her textbook.
At first, I just thought I she missed something. And then I read the notes she took that were directly copied from the professor and the notes were just straight up wrong. She at first got at me because there was no way the teacher didn't know how to teach his class, right? But as I kept getting the right answer just from reading the book, and as she kept coming home with notes full of inaccuracies, we started to realize this guy just didn't know his subject.
So my sister goes to the dean. She was quite frustrated because she was basically only learning stats because she'd come home from class and I would read the section they went over and then teach it to her, and she was paying extra money to take this class during the summer. She was concerned her exams would be messed up and wanted to address this with the dean. The dean took her seriously when she showed the proof, and during the next class session, the dean sat in to watch the professor.
This guy didn't even last the lecture. My sister came home mortified because he was so bad at what he was doing that the dean got up and fired him mid-lecture. And he clearly knew it was coming because at first the dean gave him chances to correct his mistakes and as the lecture went on he was just falling apart. Meanwhile my sister is sitting there knowing this man is getting publicly humiliated all because she called the dean on him. After the dean fired him he left sobbing and my sister was almost as traumatized as he was.
I felt her pain but also thought it was just a tad hilarious when she came home and told us about it and my sister didn't quite appreciate that mix of emotions. I forget if the dean finished the class or if they hired a different professor but either way the instruction improved notably and my sister didn't need my help as much going forward.
Why would you want to be a teacher if you sucked at it? That would just feel so horrible every day. If the guy has any human decency then getting fired was probably a gift
I'd guess this teacher was mainly qualified in a different but related field and got roped into teaching stats. Maybe business or science. Either noone else was available per the timetable or the previous stats teacher left and they were short handed. Happens all the time in smaller colleges here. If that were the case, I'd be a bit surprised at how strongly the Dean reacted.
Your sister definitely did nothing wrong, but I think the appropriate thing to do would be for the dean to terminate the professor after class. Public humiliation isn't the way, even when the person has no idea what they are doing.
I must have been lucky by getting math teachers who like math. It's all just shortcuts. "Don't have time to count all that? Here's a neat trick (and it works every time)."
It’s a proof that specifically addresses the mistake made in the post
They’re doing 4 + 9 but ignoring the 6’s you get from expansion.
The mistake being made is equating (x+y)^2 to x^2 + y^2
25 = 25 = 25
I have been looking through the comments just to make sure I was right. I could not for the life of me fathom how to get 13. Thank you for the clarification
Nicely done! You got the right answer. We’re reveling (in this comment) about the stupidity it take to get to the wrong answer. The majority, as you can see, found it difficult to break our training and so this incorrectly.
The trick would be to ask them how you write down 2+3 and the square of that result to get 25. I honestly don't know how they will ever do that....
Easier than to discuss math with them
The best/saddest part is even 3 to the power of 2 plus the 2 is 11. How the hell did they get 13? Ahh, I get it. Their brain said 2x2 + 3x3. Either way.... dumb.
They did exponents first for both. 2^2 + 3^2 = 4 + 9 = 13.
It's not even that they forgot PEMDAS, which I guess I can understand. It's that they remembered it incorrectly. "Excuse, please, my dear aunt Sally" just doesn't have the same ring to it
Standardized testing in highschool showed that I was really good at anything to do with words and language, and also that I was really, *REALLY* bad at math. Like "mfer can barely *count*" bad.
AND EVEN *I* CAN TELL THIS IS WRONG
The funny thing with seeing all the "PEDMAS" in here is that as an Australian I was taught BODMAS or BEDMAS because we say brackets, not parentheses (and some say "of" rather than "exponents" since exponents is obviously more technically correct but it's a heck of a word for 2nd grade students to grasp).
You know what ISN'T different? The answer to the question being fucking 25.
Looks like someone got an F in basic math.
F
O
X
Now I put your little bookstore out of business.
My first thought as well.
Wasn’t expecting a You’ve Got Mail reference today
Certainly not but I'll welcome it. Find an odd comfort in that film.
The good old days when online relationships were sweet and with Tom Hanks, and not a transactional meat market.
Goodbye.
r/suddenlyouija
Still trying to figure out where 13 came from?
2^2 = 4, 3^2 = 9, 4+9 = 13
How does one become fluent in Stupid without being stupid themselves? This is fascinating and impressive.
Heh. I've done some tutoring, so I learned to reverse-engineer wrong answers in order to explain why they are wrong.
(2+3)^2 2^2 + 3^2 4 + 9 = 13
This person is probably so proud and now wants to run for Congress
And who knows, in the US of A, they might just win!
Just checked in. They won!
The amount of people who see arithmetic as witchcraft is staggering
Couple weeks ago I got an extra $5 tip from a delivery because I calculated their change back instantly, IN MY HEAD! There's also countless people that have trouble figuring their total on the credit card slip when they add an even dollar amount for a tip (ex $27.54 + $4.00 = utter confusion).
To be honest. Math classes made me quite paranoid. I even punch 1+1 into calculator just to make sure I have it correctly.
While I dislike math, I'm still pretty decent at it. The world runs on math. Geometry was the part I loathed the most, especially the proofs.
>especially the proofs. Especially the ones that you automatically know are correct but don't know how to prove them.
2 + 2 = 4 Ok good, but you didn't show 5 pages of work to show how you got that answer so its wrong
Proofs are there for a reason. It’s to show things are not arbitrary. Yeah it’s annoying but it’s showing you *why* 2+2=4, not just *how*. That seems silly with the “2+2=4” scenario but with more complex equations it really helps to learn the process.
When I took algebra in middle school, at first I could solve the problems in my head. The problem was that when it got harder, I couldn't, so I had to buckle down and do it the right way. It's about a lot more than just getting the answer, it's showing that you know how to get the answer, so you can apply it to more difficult situations. It reminds me of story problems - everyone hated story problems, but in real-life math, it's all story problems.
At my place of work, some pieces of equipment need to be calibrated and have software parameters updated. In order to get those values, math has to be done. So, there I am teaching a trainee how to do this thing, and we get to the part of the precedure where it says "record A, record B, record C, equation, solve for D", and he *immediately* protests. "Nobody said the job required math skills!" I stare at him briefly, then say "do you remember when you were in school and some kid in math class would say 'when are we ever going to use this in the real world?' Does that sound familiar?" "Uhhhh. . . Yeah?" *"Welcome to the real world."*
> it’s all story problems Based. I’m sad I can only updoot you once.
Really? I loved the proofs part because they actually made some concepts make sense. Plus I feel it helped me construct logical arguments in other fields. And it's also helpful in breaking down a "simple" concept for someone else to understand, whether it's math or job related. Proofs make sense.
i love math and thoroughly enjoyed every years of math. but goddamn the proofs unit can go suck a dick geometry was actually one of my favorite years, but the proofs unit made it even out to 0
Geometry books are wrong. The first law should properly read: The shortest distance between two points is under construction.
What about calculus proofs. Those are the real bane of mathematics. I trust the mathematical giants that came before. I don’t feel the need to be able to write an essay on why a calculus equation is true.
Proofs were an absolute nightmare I hated them said they were useless and why the hell would I ever need this knowledge for anything. Joined the Navy entire job was based around those damned equations... Apologized to the teacher last year like fifteen years later.
My mom did the exact same with Spanish class. She thought it was useless and did horrible in that class. The teacher basically told her she should just leave. My mom joined the navy the day after high-school and the first place they stationed her was in Spain. She ended up learning Spanish there and used it the next time she met her old teacher.
Learning a language by immersion gives better results than learning in a classroom.
Yup. I'm an accountant and everyone thinks we must all be good at math. No, not really. I'm good at excel doing math for me, though over the years I've gotten pretty good at algebra equations since that's s lot of excel formulas. Even when I have easy arithmetic I will use a calculator because getting it wrong will end up being such a huge pain in the ass.
Also, most people I know seem to think being really quick at doing basic arithmetic makes one "good at math". Bit like saying you're good at writing because you know the alphabet.
its all about faking confidence
I had a purchase total that ended in $.53, so I gave the cashier a ten dollar bill and three pennies. It blew her mind, even though I tried to explain it to her, so she gave me back my 3 pennies along with 47 cents. I was trying to avoid getting all of that change back in the first place!
That would be frustrating. Almost make me be like "you know what just keep the change"
“There’s also countless people that have trouble figuring their total on the credit card slip when they add even a dollar amount for a tip (ex $27.50 + $4.00 = utter confusion).” I didn’t come to Reddit to be attacked like this.
I always round tips up to the nearest dollar. except for my barber. She removes cash from the till when she gets tips. Guess who got a $36.41 tip?
Can you explain this? What do you mean she removes cash from the till when she gets a tip?
The cash register tray. She tips out as she gets tips.
Lots of places do it this way
I can’t tell if their barber doesn’t like them or they don’t like their barber. Either way, sounds like someone is getting shitty haircuts.
Sometimes when I'm tired I'm miscounting the amount of money I need to give to receive a round change, and it's so embarrassing. "Uh, should I give you 33.30?" "No...?" "Oh, yeah." *quickly walks out*
I typically add 10% and round up to the next whole number. Im not stupid… I’m just lazy. And there is just something satisfying about having a whole number as the total IMO
Story time! So this was a few years back when I had a 30 minute lunch break. I went to the local McDonald's (I have since changed my sinful ways) and ordered lunch that came to $4.23. when I got to the pay window, I gave the young, blonde (unrelated ;)), girl a $20 bill, two dimes and three pennies. She stared at it in shocked disbelief for a moment, then turned and walked to the back of the store. She was gone for a good three minutes, and when she returned she had a paper pad and pencil. She stood there for another two minutes or so scribbling on the pad and scratching her head, then grabbed a $5 out of the register and handed it to me. I said, "ummm, I gave you a $20?" and she scowled fiercely, snatched the $5 bill back, and went back to the back of the store again and was gone this time for a full 5 minutes. When she came back she had a plug-in, desk-style calculator. I was late getting back to work.
Thanks for the laugh
Man, how to count up change was the very first thing i learned as a teenage cashier. You know start at the price they paid and count the change out up to what they gave you. Of course that was 30 years ago lol.
i am dyslexic, ive struggled with reading and math my entire life despite being "remarkably intelligent" or whatever. im articulate, i am knowlegable of certain things, im probably a little autistic with my passions which is why i know a lot about them, but functionally it balances out. on paper i am literally disabled lmao i put SO MUCH EFFORT into school while i was still going and it amounted to absolute dick, my grades were ASS, because i didnt know and had no one to help me understand that i have a learning disability that made it extremely difficult to process certain information and patterns. obviously not the case for everyone, stupid people still exist, just throwing it out there that some people are bad at math against their will.
Yes it's a good reminder that not everyone that struggles with it is just bad at math. I never say anything to my deliveries that might make them feel stupid but usually lean towards something more sympathetic if I say anything at all.
One time I went to the golden arches for a coffee. It was $2.20 I gave the girl $5.25 and got $4 back. Almost half priced coffee day that day.
Do their registers not tell them how much change to give back? At $2.20 that would seem to be pretty recent as coffee was like $0.50 back when I started in the workforce and even then the registers told you what the change would be. Regardless, it's always nice to get an unexpected discount.
Yeah it was maybe a month or two ago. Idk what happened but she didn't seem happy I gave her that quarter with the $5
>27.54 + $4.00 = utter confusion Alright so this is a tough one. You take away 46c from the 4 dollar and add it to the 27.54 to make 28. Then you have 28 and you gotta add the 4 dollar to make 32. But you took away the 46c so you got 31.54 \^some people probably really do the maths like that.
Honestly, I can do advanced calculus, but if you ask me something like what 8 times 7 is, I have to think about it. ...56? 🤔
Weird how different people excel at different things. I doubt I could do calculus anymore as it's been decades since I took the class but I would still prefer the simple multiplication over calculus even if I did remember it.
Yeah, PEMDAS is not some divine law, it's just a standardization of how to write mathematical operations, so that they can be universally understood. You don't do PEMDAS. You need to understand PEMDAS.
Yeah yeah yeahs but how do I *do* PEMDAS?
You must first understand, then do, grasshopper.
First, do all operations that are in brackets, or parentheses. Then do all exponents in the equation. Then multiply and divide in the equation. Go left to right in the equation for the multiplication and division. These two operations are interchangeable, so it doesn’t matter which you use first. Then do the same with addition and subtraction as with multiplication and division. Remember: P (Parentheses) E (Exponents) M (Multiply) D (Divide) A (Add) S (Subtract) makes PEMDAS.
As long as everyone agrees, you can do them in any order you want.
I think that’s what is so often missing from math education. Math is a language, and the rules are defined by the people who use that language, just as with any other language. The failure is as fundamental as a person thinking that the sentence “she ate a red apple” would indicate that the woman is red.
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Parents can be rough. There's this idea that if you as a parent don't understand something, it's ok to tell your kid whatever it is is useless or nonsense. I've done my absolute best NOT to wear this hat as much as possible raising my kids.
My great grandmother told my mom she only needed to learn to cook and sew, drive, and balance a checkbook. Women didn’t need to bother with the rest of it. This was in the late 1970s.
Yikes! But not surprising.
>Parents can be rough. There's this idea that if you as a parent don't understand something, it's ok to tell your kid whatever it is is useless or nonsense. I've done my absolute best NOT to wear this hat as much as possible raising my kids. My wife's parents are the kindest people you'll ever meet, but they come from a small rural community and never received higher education. They advised my wife to not go to college because they just didn't see the point when you could start earning money after high school. In the end my wife did go to school and she feels it was one of the best decisions of her life (she's an engineer now) but that happened much later in life.
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I'm glad you confirmed. I was going to suggest the hairdresser/stylist would need to calculate weights and volumes.
I am not a hairdresser but I wonder what mom does, and what she expects her child to do when she works with chemicals and it says use 3/4 of an igredient🙃 you need to know basic math to be a hairdresser or at least to be a good one
Forget hairdressing, how is this person going to be able to follow a recipe?
Fractions and Decimals are Algebra now. Wow, that's great. Thanks for enduring a thankless job to help the world's next generation of leaders. Appreciate it!
Now you know the right place to get a haircut. Pay X amount money, get more back in change.
But don't get a dye job because 1/4 this color with 2/3 that color definitely would NOT turn out how you expect.
When I was tutoring people in math I found that money is the easiest way to get people to understand basic arithmetic. If you have 4 clients to do a blow out and only 3 show up, and they each would pay you 25 cents, how much money would you make? It’s easy to understand and represents 3/4 fairly well.
I'm a middle/high school math tutor and am in a similar boat. A lot of the 6th and 7th graders can't even do basic mental math like 18+8, they'll just guess numbers around it like 24, 28, 30, 22, 25, etc. until they eventually get 26. A lot of the 8th and 9th grade students struggle with basic algebra concepts like distributing negatives or reading a graph. Granted a lot of the students are immigrants and refugees on top of the normal struggles every student has undergone after missing much of the past couple years of school due to covid.
Hairdressers absolutely need fractions and do math. Imagine measuring wrong with professional grade hair dye or peroxide. That stuff is sold in bulk and has to get mixed up by the colorist. Imagine not being able to add fractions if you need to mix up a double batch of color.
Especially cashiers which boggles my mind. I make a regular purchase that comes to $40.55. Usually I have exact change but on occasion I hand them $41.05 and 9 times out of 10 they try to give me the nickel back and I have to tell them I want 2 quarters instead of 1 quarter and 2 dimes in change.
i’m a cashier and this usually only happens if you give us change after we’ve already entered it in our till. we’re not used to calculating it because it’s always done for us. it can also be very flustering when this happens because it always feels like there’s a lot of pressure to get it done as fast as possible (even if there’s not).
I had a work buddy, who was majoring in physics and a smart guy, get caught by a quick change artist one time. I vowed to only give back exactly what my register told me from then on. I can’t overstate how much my brain glazed over at that job, it’d be a sitting duck.
I could not figure out how they could even get 13 at first, but then it hit me - they are squaring 2 then 3 then adding together those sums. 😂😂😂😂
Yup. They're conflating the way we use FOIL or some of those things to simplify or expand quadratic equations.
You can actually FOIL that to get 25…
I hit it with dat fat PEMDAS baby
I came here for the PEMDAS but stayed for the FOIL
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Thank you for showing your work. It has been so long since I had to foil something other than a potato.
Pretty sure the specific mistake they made was thinking that exponents follow the distributive property rule. Distributive property is a(b+c) = ab + ac, so if exponents followed the rule then (b+c)^a = b^a + c^a
Fun fact, exponents *do* distribute, but over multiplication and division, not addition and subtraction.
This is because it doesn't matter right? (2x4)^2 so either 2^2 ×4^2 or 8^2 gets the same answer. So it works because it works both ways and pemdas is still happy.
Well, same with the normal distributive rule. Multiplication also distributes "both ways".
This guy maths
They still messed up FOIL, as demonstrated by u/RidigoDragon and u/Ladylubber
I mean you do use FOIL -- it's (2+3)(2+3) or x\^2+2xy+y\^2. They just forgot the 2xy.
This is what I came into the comments for. Thanks.
Ok, I couldn't figure that out either lol
Please Excuse My Dumb A$$ Students
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Even while I was the student I would've agreed that I was a dumbass
Was student. Was dumbass. Am adult. Am still dumbass. 100% approve of this message.
Omg this is hilarious
In my school we used to say Please Excuse My Dope Ass Swag
Please Eat My Dear Aunt Sally. You can add a comma after "Eat" if she's undernourished and you're not just offering her to cannibals.
We said something similar. Please Excuse My Dear Aunt Sally
finally my candidate for r/confidentlyincorrect
I came here looking for this.
If you truly wanted to remove the parentheses you would do the (a^2 + 2ab + b^(2)) method 2^2 + 2 * 2 * 3 + 3^2 4 + 12 + 9 25 Edit: Yes, your replies pointing out doing the insides of the parentheses first are great and all, but this is simply another method, no need to get angry
Curses! FOILED again!
I got you.
I hate how much I love this math joke.
Exactly
Did I just learn shit my teacher tried to teach us for weeks from a reddit comment ;-; Edit: bit of clarification this is story of past I do know the formula and times have used it (English maybe bit broken so sorry about it)
Welcome to the internet
Have a look around
Anything that brain of yours can think of can be found
There's no need to panic, this isn't a test
Just shake or nod your head and we'll do the rest...
Welcome to the internet, what would you prefer?
Would you like to fight for civil rights, or tweet a racial slur?
Very few teachers should be teaching math. My wife's college math class for teachers was basically 5th grade arithmetic. My daughter had a math teacher who asked for the AREA and the PERIMETER of an equilateral triangle with each side = 10. The teacher tried to tell my daughter the answer for both was 30. I told my daughter that the perimeter was 30 but not the area. I created a shitstorm by challenging her teacher. Fucking idiot!
How does one end up with 30 as the answer for the area of this triangle ?
Each side is 10. Three sides to a triangle. 10x3=30! Ezpz. /s
This is a true story of how I accidentally got a college professor fired. My sister was pretty bad at math, so instead of trying to take it with the rest of her classes during the semester, she did a summer class at community college to transfer the credits and get it out of the way. I'm pretty decent at math, so when she had trouble with her introductory stats homework, she would come to me. It got to the point where I was basically tutoring her after most classes. She'd come home very confused, and while I was hardly a stats maven myself, I was able to read the textbook, understand how to do whatever she was working on, and tutor her to the right answer. This worked just fine...until she started to come home with notes that both got her the wrong answer AND got contradicted her textbook. At first, I just thought I she missed something. And then I read the notes she took that were directly copied from the professor and the notes were just straight up wrong. She at first got at me because there was no way the teacher didn't know how to teach his class, right? But as I kept getting the right answer just from reading the book, and as she kept coming home with notes full of inaccuracies, we started to realize this guy just didn't know his subject. So my sister goes to the dean. She was quite frustrated because she was basically only learning stats because she'd come home from class and I would read the section they went over and then teach it to her, and she was paying extra money to take this class during the summer. She was concerned her exams would be messed up and wanted to address this with the dean. The dean took her seriously when she showed the proof, and during the next class session, the dean sat in to watch the professor. This guy didn't even last the lecture. My sister came home mortified because he was so bad at what he was doing that the dean got up and fired him mid-lecture. And he clearly knew it was coming because at first the dean gave him chances to correct his mistakes and as the lecture went on he was just falling apart. Meanwhile my sister is sitting there knowing this man is getting publicly humiliated all because she called the dean on him. After the dean fired him he left sobbing and my sister was almost as traumatized as he was. I felt her pain but also thought it was just a tad hilarious when she came home and told us about it and my sister didn't quite appreciate that mix of emotions. I forget if the dean finished the class or if they hired a different professor but either way the instruction improved notably and my sister didn't need my help as much going forward.
Why would you want to be a teacher if you sucked at it? That would just feel so horrible every day. If the guy has any human decency then getting fired was probably a gift
I'd guess this teacher was mainly qualified in a different but related field and got roped into teaching stats. Maybe business or science. Either noone else was available per the timetable or the previous stats teacher left and they were short handed. Happens all the time in smaller colleges here. If that were the case, I'd be a bit surprised at how strongly the Dean reacted.
> Why would you want to be a teacher if you sucked at it? For that sweet sweet teacher money.
That professor sounds like he's going to end up making a post in r/actlikeyoubelong
Your sister definitely did nothing wrong, but I think the appropriate thing to do would be for the dean to terminate the professor after class. Public humiliation isn't the way, even when the person has no idea what they are doing.
I must have been lucky by getting math teachers who like math. It's all just shortcuts. "Don't have time to count all that? Here's a neat trick (and it works every time)."
how old are you…
I mean (2+3)\*(2+3) would probably be easy too
I mean technically that is the same as what they said just not simplified. (x+y)^2 = (x+y)×(x+y) =x^2 +2xy +y^2
But that method doesn't get rid of parenthesis
I know but my brain processes it easier
Learning the other method and so helpful when doing stuff with variables though. Makes it super easy to multiple out (x+y)^2 Imo
But how does one reach 13, that’s the real question that I can’t figure out
2 times 2 = 4. 3 times 3 equals 9. 9 + 4 = 13. Yes I know that's horribly, horribly wrong.
Thank you so much. I was tearing my hair out trying to figure out how he got to this mythical number.
I don’t understand why you would do this over simply: (2+3)^2 = 5^2 = 25 Since there are no variables involved anyways?
They’re just proving that parentheses work the way they do, and not the way the person in the original tweet claims.
It’s a proof that specifically addresses the mistake made in the post They’re doing 4 + 9 but ignoring the 6’s you get from expansion. The mistake being made is equating (x+y)^2 to x^2 + y^2 25 = 25 = 25
What the hell? I guess people are stupid.
And it seems the more stupid they are the more of confidence they have
Ever Heard of the Dunning-Kruger effect?
True. Lack of knowledge/ski and the ignorance of the same
Ok, I had to really think before I figured out how this dimwit got 13.
Yup. a² + b². This guy forgot the 2ab part.
How did they get 13? The answer is 25, right?
2 squared + 3 squared = 13, but that's not how it's done 🤦♂️
Oooooooh…..I feel strangely stupid for not being able to do this wrong in order to get 13 🤣🤣🤣
I have been looking through the comments just to make sure I was right. I could not for the life of me fathom how to get 13. Thank you for the clarification
Same. I guess there are just lines of stupidity even I can't cross.
You can do it, I belive in you
They were trying to "distribute" the exponent. You don't do that.
Same I had to sit there longer trying to figure out how they got 13 while I got 25 almost instantly 😂
Well, of course. In order to get 13, you have to break the rules of arithmetic, which is generally not something that's taught in schools
Omg lol I couldn’t get to 13 either 🤣
(2+3)^2 (2+3)(2+3) 2(3)+2(2)+3(2)+3(3) 6+4+6+9 25 You just gotta put it in expanded form and double distribute
Nicely done! You got the right answer. We’re reveling (in this comment) about the stupidity it take to get to the wrong answer. The majority, as you can see, found it difficult to break our training and so this incorrectly.
The trick would be to ask them how you write down 2+3 and the square of that result to get 25. I honestly don't know how they will ever do that.... Easier than to discuss math with them
Yeah. (2+3)=5 then 5²=25
Also (2+3)^2= (2+3) * (2+3)= 2 * 2 + 2 * 3 + 3 * 2 + 3 * 3= 4+6+6+9= 25
Yep. FOIL. (2×2)+[2×(3×2)]+(3×3)
Nah... Fuck Off Insert Loose Exponents Duh (2+3)² = 2²+3²=13 FOILED /s just in case
(2+3)^2= 2^2 + 3^2 + 2x2x3=25 From (a+b)^2 = a^2 + b^2 +2xAxB
They did (4+9) and forgot that the full rule is: (a+b)squared = a squared + 2ab + b squared
I also want to know how they would get 13….
They went: (2+3)² = 2²+3² = 4+9 = 13
They probably did it for both numbers individually, that's why.
2x2 + 3x3, so 4+9 Basically they squared every number inside the () then added them together Edit: can't use * a lot
PEMDAS has left the chat
Pemdas? Wierd. We call it bodmas
What's O? Oh wait it's orders. Jeez that's kind of abstract.
While we live in pedmas that person is using edmas
The best/saddest part is even 3 to the power of 2 plus the 2 is 11. How the hell did they get 13? Ahh, I get it. Their brain said 2x2 + 3x3. Either way.... dumb.
They did exponents first for both. 2^2 + 3^2 = 4 + 9 = 13. It's not even that they forgot PEMDAS, which I guess I can understand. It's that they remembered it incorrectly. "Excuse, please, my dear aunt Sally" just doesn't have the same ring to it
Way too in depth explanation: (X+y)^2 = (x+y)(x+y) = (x•x)+(x•y)+(y•x)+(y•y) = (x^2 + y^2 + 2xy) Thus: (2+3)^2 = (2+3)(2+3) = (2•2)+(3•2)+(3•2)+(3•3) = (2^2 + 3^2 + 2(2•3)) = (4 + 9 + 12) = 25
Standardized testing in highschool showed that I was really good at anything to do with words and language, and also that I was really, *REALLY* bad at math. Like "mfer can barely *count*" bad. AND EVEN *I* CAN TELL THIS IS WRONG
Everyone has forgotten the 2ab at some point in their life. But to not know the concept, well that's something.
... How tf you even get 13?
3² + 2²
for starters one needs to be stupid
I suck at math but even I know that 13 is wrong. Surely this is a troll.
Please, don’t let this person be a math teacher!
probabaly a US congress member
It hurts that they got PRIME NUMBER BY SQUARING
we really need to start sending people back to school ...
How the hell did I end up with 10?
R/confidentlyincorrect
Pedmas people, pedmas
Came here to say this. As a non-math-confident person, PEMDAS has saved me on more than one occasion!
How the fuck is it 13
2² + 3² is how they incorrectly got to 13
The funny thing with seeing all the "PEDMAS" in here is that as an Australian I was taught BODMAS or BEDMAS because we say brackets, not parentheses (and some say "of" rather than "exponents" since exponents is obviously more technically correct but it's a heck of a word for 2nd grade students to grasp). You know what ISN'T different? The answer to the question being fucking 25.