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Proof Writing Help
gulab_jamun   1
N 3 hours ago by Gavin_Deng
Ok so like, i'm working on proofs, and im prolly gonna use this page for any questions. My question as of now is what can I cite? Like for example, if for a question I use Evan Chen's fact 5, in my proof do I have to prove fact 5 all over again or can i say "this result follows from Evan Chen's fact 5"?
1 reply
gulab_jamun
5 hours ago
Gavin_Deng
3 hours ago
for the contest high achievers, can you share your math path?
HCM2001   30
N 3 hours ago by mhgelgi
Hi all
Just wondering if any orz or high scorers on contests at young age (which are a lot of u guys lol) can share what your math path has been like?
- school math: you probably finish calculus in 5th grade or something lol then what do you do for the rest of the school? concurrent enrollment? college class? none (focus on math competitions)?
- what grade did you get honor roll or higher on AMC 8, AMC 10, AIME qual, USAJMO qual, etc?
- besides aops do you use another program to study? (like Mr Math, Alphastar, etc)?

You're all great inspirations and i appreciate the answers.. you all give me a lot of motivation for this math journey. Thanks
30 replies
HCM2001
May 21, 2025
mhgelgi
3 hours ago
Convolution of order f(n)
trumpeter   76
N 4 hours ago by ray66
Source: 2019 USAMO Problem 1
Let $\mathbb{N}$ be the set of positive integers. A function $f:\mathbb{N}\to\mathbb{N}$ satisfies the equation \[\underbrace{f(f(\ldots f}_{f(n)\text{ times}}(n)\ldots))=\frac{n^2}{f(f(n))}\]for all positive integers $n$. Given this information, determine all possible values of $f(1000)$.

Proposed by Evan Chen
76 replies
trumpeter
Apr 17, 2019
ray66
4 hours ago
9 USAMO/JMO
BAM10   26
N Today at 1:36 PM by neeyakkid23
I mock ~90-100 on very recent AMC 10 mock right now. I plan to take AMC 10 final fives(9th), intermediate NT(9th), aime A+B courses in 10th and 11th and maybe mathWOOT 1 (12th). For more info I got 20 on this years AMC 8 with 3 sillies and 32 on MATHCOUNTS chapter. Also what is a realistic timeline to do this
26 replies
BAM10
May 19, 2025
neeyakkid23
Today at 1:36 PM
[TEST RELEASED] OMMC Year 5
DottedCaculator   110
N Today at 12:14 PM by PikaPika999
Test portal: https://ommc-test-portal-2025.vercel.app/

Hello to all creative problem solvers,

Do you want to work on a fun, untimed team math competition with amazing questions by MOPpers and IMO & EGMO medalists? $\phantom{You lost the game.}$
Do you want to have a chance to win thousands in cash and raffle prizes (no matter your skill level)?

Check out the fifth annual iteration of the

Online Monmouth Math Competition!

Online Monmouth Math Competition, or OMMC, is a 501c3 accredited nonprofit organization managed by adults, college students, and high schoolers which aims to give talented high school and middle school students an exciting way to develop their skills in mathematics.

Our website: https://www.ommcofficial.org/

This is not a local competition; any student 18 or younger anywhere in the world can attend. We have changed some elements of our contest format, so read carefully and thoroughly. Join our Discord or monitor this thread for updates and test releases.

How hard is it?

We plan to raffle out a TON of prizes over all competitors regardless of performance. So just submit: a few minutes of your time will give you a great chance to win amazing prizes!

How are the problems?

You can check out our past problems and sample problems here:
https://www.ommcofficial.org/sample
https://www.ommcofficial.org/2022-documents
https://www.ommcofficial.org/2023-documents
https://www.ommcofficial.org/ommc-amc

How will the test be held?/How do I sign up?

Solo teams?

Test Policy

Timeline:
Main Round: May 17th - May 24th
Test Portal Released. The Main Round of the contest is held. The Main Round consists of 25 questions that each have a numerical answer. Teams will have the entire time interval to work on the questions. They can submit any time during the interval. Teams are free to edit their submissions before the period ends, even after they submit.

Final Round: May 26th - May 28th
The top placing teams will qualify for this invitational round (5-10 questions). The final round consists of 5-10 proof questions. Teams again will have the entire time interval to work on these questions and can submit their proofs any time during this interval. Teams are free to edit their submissions before the period ends, even after they submit.

Conclusion of Competition: Early June
Solutions will be released, winners announced, and prizes sent out to winners.

Scoring:

Prizes:

I have more questions. Whom do I ask?

We hope for your participation, and good luck!

OMMC staff

OMMC’S 2025 EVENTS ARE SPONSORED BY:

[list]
[*]Nontrivial Fellowship
[*]Citadel
[*]SPARC
[*]Jane Street
[*]And counting!
[/list]
110 replies
DottedCaculator
Apr 26, 2025
PikaPika999
Today at 12:14 PM
Proof-based math
imbadatmath1233   5
N Today at 3:19 AM by LearnMath_105
Okay, I need help in deciding on how i am going to prep. My JMO index was 121.5+11 = 231.5(10A) and I missed the cutoff by 1.5. Ive already grieved about this before but I need some help in deciding what I should do next year. I think I can make JMO but my goal is to get 21+ on JMO. However, OTIS applications are already done so does anyone have any other tips on how to prep for JMO. Any help would be very much appreciated. Also, how much time should i spend on computational if i want to prep for olympiad but I don't want to get rusty. Thanks for helping!
5 replies
imbadatmath1233
Yesterday at 11:06 PM
LearnMath_105
Today at 3:19 AM
Awesome Math Rec Letter
cowstalker   0
Today at 12:18 AM
Hello, I recently looked at the MIT Primes website and saw that they accept recommendation letters from the Awesome Math Summer Program. Has anyone ever gotten a recommendation letter from one of the teachers in Awesome Math? I'm also planning to take AMSP and would like to get a rec letter from my teacher, too, so I was wondering if this is even possible or not.
0 replies
cowstalker
Today at 12:18 AM
0 replies
Circles, Lines, Angles, Oh My!
atmchallenge   19
N Yesterday at 10:47 PM by kilobyte144
Source: 2016 AMC 8 #23
Two congruent circles centered at points $A$ and $B$ each pass through the other circle's center. The line containing both $A$ and $B$ is extended to intersect the circles at points $C$ and $D$. The circles intersect at two points, one of which is $E$. What is the degree measure of $\angle CED$?

$\textbf{(A) }90\qquad\textbf{(B) }105\qquad\textbf{(C) }120\qquad\textbf{(D) }135\qquad \textbf{(E) }150$
19 replies
atmchallenge
Nov 23, 2016
kilobyte144
Yesterday at 10:47 PM
another diophantine about primes
AwesomeYRY   133
N Yesterday at 9:19 PM by EpicBird08
Source: USAMO 2022/4, JMO 2022/5
Find all pairs of primes $(p, q)$ for which $p-q$ and $pq-q$ are both perfect squares.
133 replies
AwesomeYRY
Mar 24, 2022
EpicBird08
Yesterday at 9:19 PM
MAA finally wrote sum good number theory
IAmTheHazard   96
N Yesterday at 4:54 PM by megahertz13
Source: 2021 AIME I P14
For any positive integer $a,$ $\sigma(a)$ denotes the sum of the positive integer divisors of $a.$ Let $n$ be the least positive integer such that $\sigma(a^n)-1$ is divisible by $2021$ for all positive integers $a.$ Find the sum of the prime factors in the prime factorization of $n.$
96 replies
IAmTheHazard
Mar 11, 2021
megahertz13
Yesterday at 4:54 PM
a