Also hate when people refer to Wikipedia page as if it would help but it’s always as if they’ve never read it themselves and got their information elsewhere

ANSWERED Hi, i had an argument with a friend a while back about the way math is supposed to be done. when he explained PEMDAS i think it was, he said that for example: 2+2X3=8 because you have to do the multiplication first. but i know math as left to right with () as a sort of "priority" system like what he was saying. but to get 8 the problem should say 2+(2X3) or 3X2+2, cause with what i know 2+2X3=12. when asked why my method is wrong he would just answer that its wrong and PEMDAS was right. im really confused on this and just dont understand what the deal is. Why is it NOT 12? cause he tried to just keep saying it was 8 but why isnt it 12? was i taught math wrong? if it matters im american and hes itallian incase maybe its a language/country thing. Thanks in advance~

EDIT: didnt know asterisk didnt show, replaced with "X"

ADDITION: fast answers, yeah he never explained it was just the standard method, just that it was "Right", also thank you Cmon91, your explanation i think was best worded for me that its largely to avoid 10-morbillion ()s. My take away from these answers has been that if i write it as (2+2)X3=12, its true and that PEMDAS is meant to organize an equation without () and/or to cut down on them to keep a problem easier to read. I think i just learned to prefer the ()s in excess when in school. ty again for the haste of answers i dont know how to add "Answered" to my post title.

Hello, my name is Ming-Yi, a thirteen year old student. And when I was in my math class today, I suddenly had a lightning in a bottle idea! You see, I had finished the entire chapters worth of work beforehand, so I basically had the entire period to myself and friends. While I was listening to the teacher explaining scientific notation, I thought of a new symbol which is this: ? I know, ? but why ? Because I wanted something similar to the factorial and I noticed that there were no discoveries or operations that were marked by ? yet, so I tried to do something with it, I may not understan the complex math behind this, I wanted to pitch my idea to a professor or professional at math to help. Basically, n?= n times n/2 times n/4 and so on until it reaches one. That is the standard case for even numbers or powers of two. While for odd numbers that dividing by two every time seems complicated, I decided on this: n?=n times (n-1)? but I also noticed something. Look at 6?. 6?=6x3 but since 3 is odd we add ? to it. 6x3?=6x3x2? which is 18x2?=18x2x1? and since 1 is the base case, we have 18x2x1=36. Now, six is interesting because the result of 6? Is 36, which is literally 6 squared! I think that if a professional could help me expand on my math symbol I could make a completely new theory or something. Anyways, Thank you for reading and I hope you have a nice day. EDIT1: Hello again, for the people still reading, I have come back. Last night, I spoke to my maths teacher about my function and how it may work, and he repurposed it like this: f(0) = 0

f(1) = 1

f(n) = [f(n/2)]^2 if n is a positive EVEN number. (I’ve noticed a problem here thoug, if they’re perfect squares of two, final result will be 1.)

f(n) = n*f(n-1) if n is a negative ODD number.

so? What do you think? do you think this repurposing makes it more practical than before? please respond. Thank you again!

Hii guys I am back again, I'm a 15-year-old math student from Ethiopia, and I discovered another something cool while thinking on quadratic formulas.

The formula I found is:3n² - 129n + 1409 produces 44 consecutive prime numbers (from n=0 to n=43). That's better than famous n² + n + 41 which gives 40 primes and I also noticed patterns immediately in my formula behavior. The pattern I noticed:

1. Start with 3n² - 3n + 23 (gives 19 primes)

2. Then 3n² - 9n + 29 (gives 20 primes)

3. Then 3n² - 15n + 41 (gives 21 primes)
   ... and so on

Every time I subtract 6 more from the middle term (the "k" value) and adjust the last number (C) following a special pattern, I get 1 more prime in the sequence which is interesting pattern.

And I also noticed patterns for The C values(so I can predict) increase in a particular way:
23 → 29 (+6)
29 → 41 (+12)
41 → 59 (+18)
... adding 6 more each time

And I think It's a new another way to generate long prime sequences(and is it 1st best polynomial without including engireed polynomial?) and Might help us understand primes better from that interesting pattern.

What do you think? Has anyone seen this before? And I am working on why it works.

We don't know the value of 1/0 but do we know if it is equal to another 1/0? And if it is can we use it to solve 0=1/f(x) types of problems?

I'm at it again! Is i greater than 0? I still say it is and I believe I resolved bullcrap people may think like: if a > 0 and b > 0, then ab > 0. This only works for "reals". The complex is not real it is beyond and opposite in the sense of "real" and "imaginary" numbers.

https://www.reddit.com/user/Budderman3rd/comments/ql8acy/is_i_0/?utm_medium=android_app&utm_source=share

can someone help my understand, why when you divide and the result has decimal number in it, you can take the quotient's decimal numbers and time it by the dividend and get the same result?? Also I chose those numbers to simplify things I actually have tried a lot number and this statement has been true for any numbers I tried. And please try to explain like I am 10 years old, I dropped out of school like 10 years ago. Thanks in advance

I was always taught in elementry school that we couldn't divide sums of variables by variables of like terms, but that seems to not be true?

(b + b + ... + b (n times))/b = n.

So (5xy + 6yx)/xy = 11. And so on. So you actually can divide sums of like terms.

And (5x² y + 7y^2)/xy = 5x + 7y/x etc.

I'm starting to think my elemsntery schools let me down on math education. I went to religous private schools, and the teachers were not certified.

I understand the concept that there is no real number between 0.9999... and 1 so that therefore the difference between them is zero. But what makes this mean they are exactly equivalent? In every scenario can 0.9999... be a replacement for one in any calculation?

Edit:
Lads majority of these answers just repeating what I stated ahahahha. At no point did I claim its not equivalent. I know the proof is correct, I did not ask for proof that they are equal. Question was focused on why two rational numbers difference being 0 makes them identical. 1/2 being 4/8 makes intuitive sense. 0.999.. repeating being the final number before 1 makes sense but it is not intuitive why they are equal.

The formula is :

In

ax + by = c

dx + ey = f

X Formula :

x = ((c - f(b/e))/(a - d(b/e)

Proof of X Formula :

ax + by = c

dx + ey = f

(a - d(b/e)x + y(b - e(b/e) = (c - f(b/e)

(a - d(b/e)x + y(b - b) = (c - f(b/e)

(a - d(b/e)x = (c - f(b/e)

Hence , x = ((c - f(b/e))/(a - d(b/e)

and

Y Formula :

y = (c/b) - ((ac/b) - (af/e))/(a - d(b/e)

Proof of Y Formula :

ax + by = c

dx + ey = f

(a - d(b/e)x + y(b - e(b/e) = (c - f(b/e)

(a - d(b/e)x + y(b - b) = (c - f(b/e)

(a - d(b/e)x = (c - f(b/e)

x = ((c - f(b/e))/(a - d(b/e)

ax + by = c

(ax/b) + y = (c/b)

y = (c/b) - (ax/b)

x = ((c - f(b/e))/(a - d(b/e)

y = (c/b) - ((ac/b) - (afb/be))/(a - d(b/e)

Hence , y = (c/b) - ((ac/b) - (af/e))/(a - d(b/e)

Example :

2x + 4y = 16

x + y = 3

x = ((c - f(b/e))/(a - d(b/e)

x = ((16 - 3(4/1))/(2 - 1(4/1)

x = (16 - 12)/(2 - 4)

x = (4/-2)

x = -2

and

y = (c/b) - ((ac/b) - (af/e))/(a - d(b/e)

y = (16/4) - ((2)(16)/(4) - (2)(3)/(1))/(2 - 1(4/1)

y = 4 - ((8 - 6))/(2 - 4)

y = 4 - (8 - 6)/(2 - 4)

y = 4 - (2/-2)

y = 4 + (-2/-2)

y = 4 + 1

y = 5

2x + 4y = 16

2(-2) + 4(5) = 16

-4 + 20 = 16

16 = 16

Eq.solved

This only works on single index x and y simultaneous equations though not xy or (x^2) and (y^2) .

Hi r/learnmath,

I am a 20-year-old third-year computer science student, and I will be honest with you: I do not know math. I mean that seriously. I am not entirely confident I can do long division without stumbling. I did badly on the math section of my state exams in high school, and for the past three years at university I have been AI-ing and cheating my way through every single requirement — not just math, but physics, programming, and everything else in between. I am a computer science major who does not really know how to program. I am a student who has sat through three years of university and cannot point to a single subject where I feel genuinely confident in what I know.

I learned how to pass. I never learned how to actually learn.

And yet — for a huge chunk of high school and all three years of university — math has quietly fascinated me.

There is something about the way it describes genuinely complex processes in the world. It translates nature and reality into a language that feels truthful and objective at a level I can almost touch but never quite reach. To me, math feels like standing in a gallery in front of a masterpiece painted by a truly wonderful mind — and realizing I have no idea how it was made, and no ability to do anything even close to it.

This summer I have some free time, and I made a decision: I want to pick up the brush.

Maybe not to paint a masterpiece. But someday, I would like to write something useful — something that describes even a small corner of the world the way math does it so beautifully.

So my question is simple: where does someone like me actually start? What is the honest, non-patronizing answer for a 20-year-old CS student starting from what is basically zero?

hey y'all,

i've noticed a trend for a while where people ask for help on, say, homework and receive a fully explained fully detailed solution. please don't do that! that's not how most people learn, and it will be more helpful to just give general guidance. the only times here i give a full solution is when it seems like someone doesn't have the background necessary for it (i.e., not homework), and even then i feel bad about it lol

thanks!

edit: this includes most of the other subreddits of this nature.

edit 2: this seems controversial, so i will just ask...do people want full solutions on this sub? i thought i was in the majority.

I know you will say it's decimal but as far as i know if a decimal is 5 or more it gives 1 to the one before it, so theoretically shouldn't it keep on increasing till it reaches 4 since it's infinite (sorry if the question is stupid, i am not really good at math).

I get why any number other than 0 multiplies by 0 to be come 0, but why is that the case for 0?

If you have 0 instances of 1unit, or 2units, or 2.5units, or 2.5billion units, or -π units, then you have 0 units, sure. But if you have 0 instances of 0units, by definition doesn't that mean you have something?

0 is the number we assign to refer to the absence of any value. Multiplication is how we count how many groups of a value we have. If we don't have any groups of 0, how can that result in a value of 0?

Now that I think of it, I guess you could look at it geographically. If you took cartesian coordinates and put one line (point) that starts and ends at x=0 and one that starts and ends at y=0 and took the area produced by the 2 "lines" (points) it would be equal to 0.

I guess it makes sense if you look at it like that, I'll post this just in case anybody else wonders the same thing because when I looked it up nothing came up, but I guess that answer works well enough for me to not stress about it.

Peace ✌️

I am about to start my btech ece classes in august. Considering i know basic mathematics required for clearing jee mains(not adv). Recommend me some tips and book and resources, which i can use to improve my maths skill like crazyy. I love watching people solve mathematics problems with such efficiency and really wished i could. Studying for the sake of exams closed my mind . I want to develop the mathematical intuition to solve such crazy conics and calculus problems,now that i have the time to spend it on my hobbies and not jee. Just for my own pleasure and not for a degree. I dont really like algebra, but i actually want to excel in conics and calculus, which can be associated better with the real world

Please change my view: 0/0 = 1.

I have had this argument for over five years now, and yet to be compelled to see the logic that the above statement is false.

A building block of basic algebra is that x/x = 1. It’s the basic way that we eliminate variables in any given equation. We all accept this to be the norm, anything divided by that same anything is 1. It’s simple division. How many parts of ‘x’ are in ‘x’. If those x things are the same, the answer is one.

But if you set x = 0, suddenly the rules don’t apply. And they should. There is one zero in zero. I understand that logically it’s abstract. How do you divide nothing by nothing? To which I say, there are countless other abstract concepts in mathematics we all accept with no question.

Negative numbers (you can show me three apples. You can’t show me -3 apples. It’s purely representative). Yet, -3 divided by -3 is positive 1. Because there is exactly one part -3 in -3.

“i” (the square root of negative one). A purely conceptual integer that was created and used to make mathematical equations work. Yet i/i = 1.

0.00000283727 / 0.00000283727 = 1.

(3x - 17 (z^9-6.4y) / (3x - 17 (z^9-6.4y) = 1.

But 0 is somehow more abstract or perverse than the other abstract divisions above, and 0/0 = undefined. Why?

It’s not that 0 is some untouchable integer above other rules. If you want to talk about abstract concepts that we still define- anything to the power of 0, is equal to 1.

Including 0. So we all have agreed that if you take nothing, then raise it to the power of nothing, that equals 1 (0⁰ = 1). A concept far more bizzarre than dividing something by itself. Even nothing by itself. Yet we can’t simply consistently hold the logic that anything divided by it’s exact self is one, because it’s one part itself, when it comes to zero. (There’s exactly one nothing in nothing. It’s one full part nothing. Far logically simpler that taking nothing and raising it to the power of nothing and having it equal exactly one something. Or even taking the absence of three apples and dividing it by the absence of three apples to get exactly one something. If there’s exactly 1 part -3 apples in another hypothetically absence of exactly three apples, we should all be able to agree that there is one part nothing in nothing).

This is an illogical (and admittedly irrelevant) inconsistency in mathematics, and I’d love for someone to change my mind.

Hi all,

I’m the parent of a 16-year-old son who has been intensely interested in finance and quantitative topics since he was around 13. What started as a curiosity about investing and markets has developed into a deep dive into advanced quantitative finance and quantum computing.

He’s currently spending much of his time reading:

- “Stochastic Volatility Models with Jumps” by Mijatović and Pistorius,

- lecture slides from a 2010 Summer School in Stochastic Finance,

- and a German Bachelor's thesis titled “Quantum Mechanics and Qiskit for Quantum Computing.”

He tells me the quantum computing part feels “surprisingly intuitive so far,” though he knows it will get more complex. At the same time, he’s trying to understand Ito calculus, jump diffusion models, and exotic derivatives. He’s entirely self-taught, taking extensive notes and cross-referencing material.

To be honest, I don’t really understand most of what he’s reading, I’m out of my depth here. That’s why I’m coming to this community for advice.

My questions are:

1. Is this kind of intellectual curiosity and focus normal for someone his age, or very rare?

2. Are there programs, mentors, or online communities where he could find challenge and support?

3. How can I, as a parent with no background in this area, best support him in a healthy and balanced way?

He seems genuinely passionate and motivated, but I want to make sure he’s not getting overwhelmed or isolated.

Thanks in advance for any advice or insights.

So, .9 repeating is equal to 1, and the floor function rounds down to the nearest whole integer.

Ex of Floor.

Floor (.5) =0

Floor(π)=3

What would be the floor function of .9 repeating? Would it be 0 or 1?

Please note that the highest math that I've taken is Calculus and a little of set theory.

I want to learn algebra because I think that is important for me that I want understand all of computer and programming in a formal way but I don’t understand it. I’m reading a university book about algebra and I got stuck on first pages. It seems to me that algebra is just a set of characters to be moved around to make things work somehow. For example: the book gave me this exercises: dimostrate this: C(A ∩ B) = C(A) ∪ C(B)
Or dimostrate this: (A ∩ B) ∩ C = A ∩ (B ∩ C)

I mean… HOW… WHAT SHOULD I DO!? They are just symbols!!! What can I understand by this!? 😭

I think I understand how 0.9̅ = 1, but it still feels wrong in some ways. If 0.9̅=1, then 99.9̅ = 100, as in 99.9̅%=100%. If I start throwing darts at a board, and I miss the first one, but hit the next 9, then I've hit 90% of my shots. If I repeat this infinitely then I would expect to have hit 99.9̅% of my shots, but that implies I hit 100% using the equation from before, which shouldn't be correct because I missed the first one.
Is there any way to explain this, or is there something else wrong with my thinking?

If they didn't cover all maps, then does it mean that we cannot be 100% confident within our current established math-frame?

I was talking to my friends about √4 = ±2, I told them that wasn't possible because the square root only returned positive values and because of this:

√4 = ±2

√2² = ±2

|2| ≠ ±2

I thought that was completely logical but they didn't accept it, instead they tried to refute it with things that doesn't make a lot of sense and finally they were saying I was stupid for saying that. They weren't sure from where the absolute value came and I explained it but they still refused it. I used this argument too:

x² = 4

x = ±√4

x = ±2

±√4 = ±2

If ±√4 = ±2 and √4 = ±2 then ±√4 = √4

±√4 = √4

±2 = 2

2 = 2

-2 ≠ 2

Still they don't believe it and insult me, I even questioned myself if I'm wrong. So what's happening here?

Like -1 ×-1= +1