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k a April Highlights and 2025 AoPS Online Class Information
jlacosta   0
Yesterday at 3:18 PM
Spring is in full swing and summer is right around the corner, what are your plans? At AoPS Online our schedule has new classes starting now through July, so be sure to keep your skills sharp and be prepared for the Fall school year! Check out the schedule of upcoming classes below.

WOOT early bird pricing is in effect, don’t miss out! If you took MathWOOT Level 2 last year, no worries, it is all new problems this year! Our Worldwide Online Olympiad Training program is for high school level competitors. AoPS designed these courses to help our top students get the deep focus they need to succeed in their specific competition goals. Check out the details at this link for all our WOOT programs in math, computer science, chemistry, and physics.

Looking for summer camps in math and language arts? Be sure to check out the video-based summer camps offered at the Virtual Campus that are 2- to 4-weeks in duration. There are middle and high school competition math camps as well as Math Beasts camps that review key topics coupled with fun explorations covering areas such as graph theory (Math Beasts Camp 6), cryptography (Math Beasts Camp 7-8), and topology (Math Beasts Camp 8-9)!

Be sure to mark your calendars for the following events:
[list][*]April 3rd (Webinar), 4pm PT/7:00pm ET, Learning with AoPS: Perspectives from a Parent, Math Camp Instructor, and University Professor
[*]April 8th (Math Jam), 4:30pm PT/7:30pm ET, 2025 MATHCOUNTS State Discussion
April 9th (Webinar), 4:00pm PT/7:00pm ET, Learn about Video-based Summer Camps at the Virtual Campus
[*]April 10th (Math Jam), 4:30pm PT/7:30pm ET, 2025 MathILy and MathILy-Er Math Jam: Multibackwards Numbers
[*]April 22nd (Webinar), 4:00pm PT/7:00pm ET, Competitive Programming at AoPS (USACO).[/list]
Our full course list for upcoming classes is below:
All classes run 7:30pm-8:45pm ET/4:30pm - 5:45pm PT unless otherwise noted.

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0 replies
jlacosta
Yesterday at 3:18 PM
0 replies
k i Adding contests to the Contest Collections
dcouchman   1
N Apr 5, 2023 by v_Enhance
Want to help AoPS remain a valuable Olympiad resource? Help us add contests to AoPS's Contest Collections.

Find instructions and a list of contests to add here: https://artofproblemsolving.com/community/c40244h1064480_contests_to_add
1 reply
dcouchman
Sep 9, 2019
v_Enhance
Apr 5, 2023
k i Zero tolerance
ZetaX   49
N May 4, 2019 by NoDealsHere
Source: Use your common sense! (enough is enough)
Some users don't want to learn, some other simply ignore advises.
But please follow the following guideline:


To make it short: ALWAYS USE YOUR COMMON SENSE IF POSTING!
If you don't have common sense, don't post.


More specifically:

For new threads:


a) Good, meaningful title:
The title has to say what the problem is about in best way possible.
If that title occured already, it's definitely bad. And contest names aren't good either.
That's in fact a requirement for being able to search old problems.

Examples:
Bad titles:
- "Hard"/"Medium"/"Easy" (if you find it so cool how hard/easy it is, tell it in the post and use a title that tells us the problem)
- "Number Theory" (hey guy, guess why this forum's named that way¿ and is it the only such problem on earth¿)
- "Fibonacci" (there are millions of Fibonacci problems out there, all posted and named the same...)
- "Chinese TST 2003" (does this say anything about the problem¿)
Good titles:
- "On divisors of a³+2b³+4c³-6abc"
- "Number of solutions to x²+y²=6z²"
- "Fibonacci numbers are never squares"


b) Use search function:
Before posting a "new" problem spend at least two, better five, minutes to look if this problem was posted before. If it was, don't repost it. If you have anything important to say on topic, post it in one of the older threads.
If the thread is locked cause of this, use search function.

Update (by Amir Hossein). The best way to search for two keywords in AoPS is to input
[code]+"first keyword" +"second keyword"[/code]
so that any post containing both strings "first word" and "second form".


c) Good problem statement:
Some recent really bad post was:
[quote]$lim_{n\to 1}^{+\infty}\frac{1}{n}-lnn$[/quote]
It contains no question and no answer.
If you do this, too, you are on the best way to get your thread deleted. Write everything clearly, define where your variables come from (and define the "natural" numbers if used). Additionally read your post at least twice before submitting. After you sent it, read it again and use the Edit-Button if necessary to correct errors.


For answers to already existing threads:


d) Of any interest and with content:
Don't post things that are more trivial than completely obvious. For example, if the question is to solve $x^{3}+y^{3}=z^{3}$, do not answer with "$x=y=z=0$ is a solution" only. Either you post any kind of proof or at least something unexpected (like "$x=1337, y=481, z=42$ is the smallest solution). Someone that does not see that $x=y=z=0$ is a solution of the above without your post is completely wrong here, this is an IMO-level forum.
Similar, posting "I have solved this problem" but not posting anything else is not welcome; it even looks that you just want to show off what a genius you are.

e) Well written and checked answers:
Like c) for new threads, check your solutions at least twice for mistakes. And after sending, read it again and use the Edit-Button if necessary to correct errors.



To repeat it: ALWAYS USE YOUR COMMON SENSE IF POSTING!


Everything definitely out of range of common sense will be locked or deleted (exept for new users having less than about 42 posts, they are newbies and need/get some time to learn).

The above rules will be applied from next monday (5. march of 2007).
Feel free to discuss on this here.
49 replies
ZetaX
Feb 27, 2007
NoDealsHere
May 4, 2019
FTW tournament!
evt917   4
N 5 minutes ago by IcyFire500
[center]Since all FTW tournaments have dramatically failed, I'm trying a different format. Here is how it works:

1. Type \signup{your rating (type 800 for unrated)}

2. You will eventually be assigned to a game. I will be doing this. how i assign games

3. If you win, you get 2 points. However, if you win games in a row, you get more points per win. When you win $n$ games in a row, you score $n+1$ points instead of $2$ points. Nice, right? A tie equals $1$ point, and a loss is zero. A tie or a loss will break your win streak.

4. I do not know everybody's time preferences. Because so, I will announce in advance which two players will be playing, so they themselves can organize a game themselves. Remember, THE PLAYERS ARE ORGANIZING THE GAMES THEMSELVES!!! The format is up to them, but please make the time control at least 20 seconds. Please announce the results of the game here so i can update the scoreboard.

recommended format if you cannot decide



5. The tournament goes on until april 22nd! Extremely long, right? Note that you can still signup after the first games has started, but you will have a disadvantage because some people who signed up as soon as the tournament started already has points.

6. Once you are done with your game, I will pair you with another opponent. You may play against same people multiple times. You can also request a new partner if your's is inactive and doesn't want to play.


[rule]

Questions and Answers

All signups and ratings

[rule]

LIVE LEADERBOARD:

1st place:
2nd place:
3rd place

4th place:
5th place:
4 replies
evt917
30 minutes ago
IcyFire500
5 minutes ago
mathcounts state score thread
Soupboy0   50
N 6 minutes ago by Akang11
\begin{table}[]
\begin{tabular}{llllll}
Username & Score & Sprint & Target & Nats? & Sillies \\
     Soupboy0    &     40  &     24   &   16     &    yes  &    6     \\
         &       &        &        &       &         \\
         &       &        &        &       &        
\end{tabular}\end{table}
50 replies
Soupboy0
Apr 1, 2025
Akang11
6 minutes ago
The daily problem!
Leeoz   54
N 22 minutes ago by HacheB2031
Every day, I will try to post a new problem for you all to solve! If you want to post a daily problem, you can! :)

Please hide solutions and answers, hints are fine though! :)

The first problem is:
[quote=March 21st Problem]Alice flips a fair coin until she gets 2 heads in a row, or a tail and then a head. What is the probability that she stopped after 2 heads in a row? Express your answer as a common fraction.[/quote]

Past Problems!
54 replies
Leeoz
Mar 21, 2025
HacheB2031
22 minutes ago
mathcounts state discussion
Soupboy0   57
N an hour ago by EightYearLetterman
les goo its finally april
57 replies
Soupboy0
Apr 1, 2025
EightYearLetterman
an hour ago
Fneqn or Realpoly?
Mathandski   2
N 2 hours ago by jasperE3
Source: India, not sure which year. Found in OTIS pset
Find all polynomials $P$ with real coefficients obeying
\[P(x) P(x+1) = P(x^2 + x + 1)\]for all real numbers $x$.
2 replies
Mathandski
4 hours ago
jasperE3
2 hours ago
thanks u!
Ruji2018252   2
N 2 hours ago by CHESSR1DER
find all $f: \mathbb{R}\to \mathbb{R}$ and
\[(x-y)[f(x)+f(y)]\leqslant f(x^2-y^2), \forall x,y \in \mathbb{R}\]
2 replies
Ruji2018252
4 hours ago
CHESSR1DER
2 hours ago
D1019 : Dominoes 2*1
Dattier   4
N 3 hours ago by Dattier
I have a 9*9 grid like this one:

IMAGE

We choose 5 white squares on the lower triangle, 5 black squares on the upper triangle and one on the diagonal, which we remove from the grid.
Like for example here:

IMAGE

Can we completely cover the grid remove from these 11 squares with 2*1 dominoes like this one:

IMAGE
4 replies
Dattier
Mar 26, 2025
Dattier
3 hours ago
Functional equations
hanzo.ei   11
N 4 hours ago by GreekIdiot
Source: Greekldiot
Find all $f: \mathbb R_+ \rightarrow \mathbb R_+$ such that $f(xf(y)+f(x))=yf(x+yf(x)) \: \forall \: x,y \in \mathbb R_+$
11 replies
hanzo.ei
Mar 29, 2025
GreekIdiot
4 hours ago
D1018 : Can you do that ?
Dattier   1
N 4 hours ago by Dattier
Source: les dattes à Dattier
We can find $A,B,C$, such that $\gcd(A,B)=\gcd(C,A)=\gcd(A,2)=1$ and $$\forall n \in \mathbb N^*, (C^n \times B \mod A) \mod 2=0 $$.

For example :

$C=20$
$A=47650065401584409637777147310342834508082136874940478469495402430677786194142956609253842997905945723173497630499054266092849839$

$B=238877301561986449355077953728734922992395532218802882582141073061059783672634737309722816649187007910722185635031285098751698$

Can you find $A,B,C$ such that $A>3$ is prime, $C,B \in (\mathbb Z/A\mathbb Z)^*$ with $o(C)=(A-1)/2$ and $$\forall n \in \mathbb N^*, (C^n \times B \mod A) \mod 2=0 $$?
1 reply
Dattier
Mar 24, 2025
Dattier
4 hours ago
D1010 : How it is possible ?
Dattier   14
N 5 hours ago by ehuseyinyigit
Source: les dattes à Dattier
Is it true that$$\forall n \in \mathbb N^*, (24^n \times B \mod A) \mod 2 = 0 $$?

A=1728400904217815186787639216753921417860004366580219212750904
024377969478249664644267971025952530803647043121025959018172048
336953969062151534282052863307398281681465366665810775710867856
720572225880311472925624694183944650261079955759251769111321319
421445397848518597584590900951222557860592579005088853698315463
815905425095325508106272375728975

B=2275643401548081847207782760491442295266487354750527085289354
965376765188468052271190172787064418854789322484305145310707614
546573398182642923893780527037224143380886260467760991228567577
953725945090125797351518670892779468968705801340068681556238850
340398780828104506916965606659768601942798676554332768254089685
307970609932846902
14 replies
Dattier
Mar 10, 2025
ehuseyinyigit
5 hours ago
iran tst 2018 geometry
Etemadi   10
N 5 hours ago by amirhsz
Source: Iranian TST 2018, second exam day 2, problem 5
Let $\omega$ be the circumcircle of isosceles triangle $ABC$ ($AB=AC$). Points $P$ and $Q$ lie on $\omega$ and $BC$ respectively such that $AP=AQ$ .$AP$ and $BC$ intersect at $R$. Prove that the tangents from $B$ and $C$ to the incircle of $\triangle AQR$ (different from $BC$) are concurrent on $\omega$.

Proposed by Ali Zamani, Hooman Fattahi
10 replies
Etemadi
Apr 17, 2018
amirhsz
5 hours ago
high school maths
aothatday   1
N 6 hours ago by waterbottle432
Source: my creation
find $f:\mathbb{R} \rightarrow \mathbb{R}$ such that:
$(x-y)(f(x)+f(y)) \leq f(x^2-y^2)$
1 reply
aothatday
Today at 2:27 PM
waterbottle432
6 hours ago
Coaxial circles related to Gergon point
Headhunter   1
N Today at 4:02 PM by internationalnick123456
Source: I tried but can't find the source...
Hi, everyone.

In $\triangle$$ABC$, $Ge$ is the Gergon point and the incircle $(I)$ touch $BC$, $CA$, $AB$ at $D$, $E$, $F$ respectively.
Let the circumcircles of $\triangle IDGe$, $\triangle IEGe$, $\triangle IFGe$ be $O_{1}$ , $O_{2}$ , $O_{3}$ respectively.

Reflect $O_{1}$ in $ID$ and then we get the circle $O'_{1}$
Reflect $O_{2}$ in $IE$ and then the circle $O'_{2}$
Reflect $O_{3}$ in $IF$ and then the circle $O'_{3}$

Prove that $O'_{1}$ , $O'_{2}$ , $O'_{3}$ are coaxial.
1 reply
Headhunter
Today at 2:48 AM
internationalnick123456
Today at 4:02 PM
Something nice
KhuongTrang   25
N Today at 3:57 PM by KhuongTrang
Source: own
Problem. Given $a,b,c$ be non-negative real numbers such that $ab+bc+ca=1.$ Prove that

$$\sqrt{a+1}+\sqrt{b+1}+\sqrt{c+1}\le 1+2\sqrt{a+b+c+abc}.$$
25 replies
KhuongTrang
Nov 1, 2023
KhuongTrang
Today at 3:57 PM
Math Competitions
anishka14   8
N Apr 1, 2025 by nmlikesmath
Hi everyone!

So I am currently in grade 6, and if anyone could give any tips for getting high scores in math competition, that would be great!

I haven't been doing so well in AMC 8, and other competitions like Math Kangaroo, etc....

I feel like i'm stuck, so if anyone could give any resources that helped you learn and score better, could you share that with me?

Thank you so much!

( also how much time should i spend on math every day? )
8 replies
anishka14
Mar 29, 2025
nmlikesmath
Apr 1, 2025
Math Competitions
G H J
G H BBookmark kLocked kLocked NReply
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anishka14
19 posts
#1
Y by
Hi everyone!

So I am currently in grade 6, and if anyone could give any tips for getting high scores in math competition, that would be great!

I haven't been doing so well in AMC 8, and other competitions like Math Kangaroo, etc....

I feel like i'm stuck, so if anyone could give any resources that helped you learn and score better, could you share that with me?

Thank you so much!

( also how much time should i spend on math every day? )
Z K Y
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Dream9
78 posts
#2
Y by
Just practice problems. A lot of problems. If your stuck then the worst thing to do is not do anything because you don't know what to do(if that makes sense). Just find problems and do them.
Z K Y
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anishka14
19 posts
#3
Y by
Where could I find practice questions?
Z K Y
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eddie.li
19 posts
#4
Y by
You can find extra problems on Alcumus
Z K Y
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Dream9
78 posts
#5
Y by
anishka14 wrote:
Where could I find practice questions?

Take past years amc 8s or math kangaroos. That's what I did. Or if you're finished with those, try to do some AOPS community-made mock tests for amc 8.
Z K Y
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iwillregretthisnamelater
18 posts
#6
Y by
Do you live in the US? Because then you’d be able to go to mathcounts
Z K Y
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anishka14
19 posts
#7
Y by
No, i'm from Canada
Z K Y
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WiseHawkCuteFriendly
565 posts
#8
Y by
which pronvince?
Z K Y
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nmlikesmath
482 posts
#9
Y by
anishka14 wrote:
No, i'm from Canada

then i don't think u can do mathcounts sry
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