Stay ahead of learning milestones! Enroll in a class over the summer!

G
Topic
First Poster
Last Poster
k a May Highlights and 2025 AoPS Online Class Information
jlacosta   0
May 1, 2025
May is an exciting month! National MATHCOUNTS is the second week of May in Washington D.C. and our Founder, Richard Rusczyk will be presenting a seminar, Preparing Strong Math Students for College and Careers, on May 11th.

Are you interested in working towards MATHCOUNTS and don’t know where to start? We have you covered! If you have taken Prealgebra, then you are ready for MATHCOUNTS/AMC 8 Basics. Already aiming for State or National MATHCOUNTS and harder AMC 8 problems? Then our MATHCOUNTS/AMC 8 Advanced course is for you.

Summer camps are starting next month at the Virtual Campus in math and language arts that are 2 - to 4 - weeks in duration. Spaces are still available - don’t miss your chance to have an enriching summer experience. 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 upcoming events:
[list][*]May 9th, 4:30pm PT/7:30pm ET, Casework 2: Overwhelming Evidence — A Text Adventure, a game where participants will work together to navigate the map, solve puzzles, and win! All are welcome.
[*]May 19th, 4:30pm PT/7:30pm ET, What's Next After Beast Academy?, designed for students finishing Beast Academy and ready for Prealgebra 1.
[*]May 20th, 4:00pm PT/7:00pm ET, Mathcamp 2025 Qualifying Quiz Part 1 Math Jam, Problems 1 to 4, join the Canada/USA Mathcamp staff for this exciting Math Jam, where they discuss solutions to Problems 1 to 4 of the 2025 Mathcamp Qualifying Quiz!
[*]May 21st, 4:00pm PT/7:00pm ET, Mathcamp 2025 Qualifying Quiz Part 2 Math Jam, Problems 5 and 6, Canada/USA Mathcamp staff will discuss solutions to Problems 5 and 6 of the 2025 Mathcamp Qualifying Quiz![/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.

Introductory: Grades 5-10

Prealgebra 1 Self-Paced

Prealgebra 1
Tuesday, May 13 - Aug 26
Thursday, May 29 - Sep 11
Sunday, Jun 15 - Oct 12
Monday, Jun 30 - Oct 20
Wednesday, Jul 16 - Oct 29

Prealgebra 2 Self-Paced

Prealgebra 2
Wednesday, May 7 - Aug 20
Monday, Jun 2 - Sep 22
Sunday, Jun 29 - Oct 26
Friday, Jul 25 - Nov 21

Introduction to Algebra A Self-Paced

Introduction to Algebra A
Sunday, May 11 - Sep 14 (1:00 - 2:30 pm ET/10:00 - 11:30 am PT)
Wednesday, May 14 - Aug 27
Friday, May 30 - Sep 26
Monday, Jun 2 - Sep 22
Sunday, Jun 15 - Oct 12
Thursday, Jun 26 - Oct 9
Tuesday, Jul 15 - Oct 28

Introduction to Counting & Probability Self-Paced

Introduction to Counting & Probability
Thursday, May 15 - Jul 31
Sunday, Jun 1 - Aug 24
Thursday, Jun 12 - Aug 28
Wednesday, Jul 9 - Sep 24
Sunday, Jul 27 - Oct 19

Introduction to Number Theory
Friday, May 9 - Aug 1
Wednesday, May 21 - Aug 6
Monday, Jun 9 - Aug 25
Sunday, Jun 15 - Sep 14
Tuesday, Jul 15 - Sep 30

Introduction to Algebra B Self-Paced

Introduction to Algebra B
Tuesday, May 6 - Aug 19
Wednesday, Jun 4 - Sep 17
Sunday, Jun 22 - Oct 19
Friday, Jul 18 - Nov 14

Introduction to Geometry
Sunday, May 11 - Nov 9
Tuesday, May 20 - Oct 28
Monday, Jun 16 - Dec 8
Friday, Jun 20 - Jan 9
Sunday, Jun 29 - Jan 11
Monday, Jul 14 - Jan 19

Paradoxes and Infinity
Mon, Tue, Wed, & Thurs, Jul 14 - Jul 16 (meets every day of the week!)

Intermediate: Grades 8-12

Intermediate Algebra
Sunday, Jun 1 - Nov 23
Tuesday, Jun 10 - Nov 18
Wednesday, Jun 25 - Dec 10
Sunday, Jul 13 - Jan 18
Thursday, Jul 24 - Jan 22

Intermediate Counting & Probability
Wednesday, May 21 - Sep 17
Sunday, Jun 22 - Nov 2

Intermediate Number Theory
Sunday, Jun 1 - Aug 24
Wednesday, Jun 18 - Sep 3

Precalculus
Friday, May 16 - Oct 24
Sunday, Jun 1 - Nov 9
Monday, Jun 30 - Dec 8

Advanced: Grades 9-12

Olympiad Geometry
Tuesday, Jun 10 - Aug 26

Calculus
Tuesday, May 27 - Nov 11
Wednesday, Jun 25 - Dec 17

Group Theory
Thursday, Jun 12 - Sep 11

Contest Preparation: Grades 6-12

MATHCOUNTS/AMC 8 Basics
Friday, May 23 - Aug 15
Monday, Jun 2 - Aug 18
Thursday, Jun 12 - Aug 28
Sunday, Jun 22 - Sep 21
Tues & Thurs, Jul 8 - Aug 14 (meets twice a week!)

MATHCOUNTS/AMC 8 Advanced
Sunday, May 11 - Aug 10
Tuesday, May 27 - Aug 12
Wednesday, Jun 11 - Aug 27
Sunday, Jun 22 - Sep 21
Tues & Thurs, Jul 8 - Aug 14 (meets twice a week!)

AMC 10 Problem Series
Friday, May 9 - Aug 1
Sunday, Jun 1 - Aug 24
Thursday, Jun 12 - Aug 28
Tuesday, Jun 17 - Sep 2
Sunday, Jun 22 - Sep 21 (1:00 - 2:30 pm ET/10:00 - 11:30 am PT)
Monday, Jun 23 - Sep 15
Tues & Thurs, Jul 8 - Aug 14 (meets twice a week!)

AMC 10 Final Fives
Sunday, May 11 - Jun 8
Tuesday, May 27 - Jun 17
Monday, Jun 30 - Jul 21

AMC 12 Problem Series
Tuesday, May 27 - Aug 12
Thursday, Jun 12 - Aug 28
Sunday, Jun 22 - Sep 21
Wednesday, Aug 6 - Oct 22

AMC 12 Final Fives
Sunday, May 18 - Jun 15

AIME Problem Series A
Thursday, May 22 - Jul 31

AIME Problem Series B
Sunday, Jun 22 - Sep 21

F=ma Problem Series
Wednesday, Jun 11 - Aug 27

WOOT Programs
Visit the pages linked for full schedule details for each of these programs!


MathWOOT Level 1
MathWOOT Level 2
ChemWOOT
CodeWOOT
PhysicsWOOT

Programming

Introduction to Programming with Python
Thursday, May 22 - Aug 7
Sunday, Jun 15 - Sep 14 (1:00 - 2:30 pm ET/10:00 - 11:30 am PT)
Tuesday, Jun 17 - Sep 2
Monday, Jun 30 - Sep 22

Intermediate Programming with Python
Sunday, Jun 1 - Aug 24
Monday, Jun 30 - Sep 22

USACO Bronze Problem Series
Tuesday, May 13 - Jul 29
Sunday, Jun 22 - Sep 1

Physics

Introduction to Physics
Wednesday, May 21 - Aug 6
Sunday, Jun 15 - Sep 14
Monday, Jun 23 - Sep 15

Physics 1: Mechanics
Thursday, May 22 - Oct 30
Monday, Jun 23 - Dec 15

Relativity
Mon, Tue, Wed & Thurs, Jun 23 - Jun 26 (meets every day of the week!)
0 replies
jlacosta
May 1, 2025
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
nice problem
math10   8
N an hour ago by TUAN2k8
Source: BMO 2008
Let $n\in\mathbb{N}$ and $0\leq a_1\leq a_2\leq\ldots\leq a_n\leq\pi$ and $b_1,b_2,\ldots ,b_n$ are real numbers for which the following inequality is satisfied :
\[\left|\sum_{i=1}^{n} b_i\cos(ka_i)\right|<\frac{1}{k}\]
for all $ k\in\mathbb{N}$. Prove that $ b_1=b_2=\ldots =b_n=0$.
8 replies
math10
Jul 28, 2009
TUAN2k8
an hour ago
Sintetic geometry problem
ICE_CNME_4   6
N an hour ago by ICE_CNME_4
Source: Math Gazette Contest 2025
Let there be the triangle ABC and the points E ∈ (AC), F ∈ (AB), such that BE and CF are concurrent in O.
If {L} = AO ∩ EF and K ∈ BC, such that LK ⊥ BC, show that EKL = FKL.
6 replies
ICE_CNME_4
Yesterday at 9:30 PM
ICE_CNME_4
an hour ago
Arbitrary point on BC and its relation with orthocenter
falantrng   30
N an hour ago by Mathgloggers
Source: Balkan MO 2025 P2
In an acute-angled triangle \(ABC\), \(H\) be the orthocenter of it and \(D\) be any point on the side \(BC\). The points \(E, F\) are on the segments \(AB, AC\), respectively, such that the points \(A, B, D, F\) and \(A, C, D, E\) are cyclic. The segments \(BF\) and \(CE\) intersect at \(P.\) \(L\) is a point on \(HA\) such that \(LC\) is tangent to the circumcircle of triangle \(PBC\) at \(C.\) \(BH\) and \(CP\) intersect at \(X\). Prove that the points \(D, X, \) and \(L\) lie on the same line.

Proposed by Theoklitos Parayiou, Cyprus
30 replies
falantrng
Apr 27, 2025
Mathgloggers
an hour ago
sum (a^2 + b^2)/2ab + 2(ab + bc + ca)/3 >=5
parmenides51   8
N an hour ago by skellyrah
Source: 2023 Greece JBMO TST p3/ easy version of Shortlist 2022 A6 https://artofproblemsolving.com/community/c6h3099025p28018726
Let $a, b,$ and $c$ be positive real numbers such that $a^2 + b^2 + c^2 = 3$. Prove that
$$\frac{a^2 + b^2}{2ab} + \frac{b^2 + c^2}{2bc} + \frac{c^2 + a^2}{2ca} + \frac{2(ab + bc + ca)}{3} \ge 5 $$When equality holds?
8 replies
parmenides51
May 17, 2024
skellyrah
an hour ago
official solution of IGO
ABCD1728   0
2 hours ago
Source: IGO official website
Where can I get the official solution of IGO for 2023 and 2024, there are some inhttps://imogeometry.blogspot.com/p/iranian-geometry-olympiad.html, but where can I find them on the official website, thanks :)
0 replies
ABCD1728
2 hours ago
0 replies
Geometry in a square
socrates   8
N 2 hours ago by AylyGayypow009
Points $M$ and $N$ lie on the sides $BC$ and $CD$ of the square $ABCD,$ respectively, and $\angle MAN = 45^{\circ}$. The circle through $A,B,C,D$ intersects $AM$ and $AN$ again at $P$ and $Q$, respectively. Prove that $MN || PQ.$
8 replies
socrates
May 18, 2015
AylyGayypow009
2 hours ago
AP Exam Leaks
acorn1234512   0
3 hours ago
Tired of studying for your AP Exams?

Look no further. Regardless of your timezone, Paul's Leaks will have ALL of the AP Exams with ALL of the versions with enough time for you to memorize (with solutions).

This happens through a DISCLOSED method. More info in the Telegram. Link below.

Have fun with your 5s, and for those who are studying, good luck.

Join the Telegram: t(dot)me/paulsleaks with or PM me on Telegram: @apleakspaul
0 replies
acorn1234512
3 hours ago
0 replies
Iran TST 2009-Day3-P3
khashi70   67
N 3 hours ago by Ilikeminecraft
In triangle $ABC$, $D$, $E$ and $F$ are the points of tangency of incircle with the center of $I$ to $BC$, $CA$ and $AB$ respectively. Let $M$ be the foot of the perpendicular from $D$ to $EF$. $P$ is on $DM$ such that $DP = MP$. If $H$ is the orthocenter of $BIC$, prove that $PH$ bisects $ EF$.
67 replies
khashi70
May 16, 2009
Ilikeminecraft
3 hours ago
1500th Post!
PikaPika999   105
N 3 hours ago by Craftybutterfly
I hit my 1500th post!!
This is just gonna be a 24 game thread then ig :)
You can't use concatenation
To start off, ig make 24 using the following numbers:

3,3,8,8

EDIT: NOTE THAT I DIDN'T MEAN TO GET THIS FROM THE TEAM CONTEST THING! I GOT THIS FROM MY FRIENDS, SO PLEASE STOP BUGGING ME ABOUT THIS
105 replies
PikaPika999
May 1, 2025
Craftybutterfly
3 hours ago
variable point on the line BC
orl   26
N 3 hours ago by Ilikeminecraft
Source: IMO Shortlist 2004 geometry problem G7
For a given triangle $ ABC$, let $ X$ be a variable point on the line $ BC$ such that $ C$ lies between $ B$ and $ X$ and the incircles of the triangles $ ABX$ and $ ACX$ intersect at two distinct points $ P$ and $ Q.$ Prove that the line $ PQ$ passes through a point independent of $ X$.
26 replies
orl
Jun 14, 2005
Ilikeminecraft
3 hours ago
Problem 2 (First Day)
Valentin Vornicu   83
N 4 hours ago by Adywastaken
Find all polynomials $f$ with real coefficients such that for all reals $a,b,c$ such that $ab+bc+ca = 0$ we have the following relations

\[ f(a-b) + f(b-c) + f(c-a) = 2f(a+b+c). \]
83 replies
Valentin Vornicu
Jul 12, 2004
Adywastaken
4 hours ago
National Team Round Problem 10?!
Leeoz   0
4 hours ago
This was the 2015 national team round problem 10...


[quote=The hardest problem in MathCounts]
In the city of Trichotomy, every day the weather is exactly one of the following:
sunny, cloudy or rainy. Each day has a 50% chance of having the same weather
as the day before and a 25% chance of having each of the other two types of
weather. If it does not rain on Friday, what is the probability that there will be
no rain during the weekend (Saturday and Sunday)? Express your answer as a
common fraction.
[/quote]
0 replies
Leeoz
4 hours ago
0 replies
BmMT Online 2025: Problem of the Week 1
BerkeleyMathTournament   2
N 4 hours ago by aidan0626
BmMT Online 2025 is in 5 weeks, register here! https://berkeley.mt/events/bmmt-2025-online/.

We'll highlight some problems for practice as the contest gets sooner -

How would you solve Relay #1, Relay #2 from last year's test?
2 replies
BerkeleyMathTournament
5 hours ago
aidan0626
4 hours ago
9 AMC 10 Prep
bluedino24   16
N 4 hours ago by Andrew2019
I'm in 7th grade and thought it would be good to start preparing for the AMC 10. I'm not extremely good at math though.

What are some important topics I should study? Please comment below. Thanks! :D
16 replies
bluedino24
Friday at 9:42 PM
Andrew2019
4 hours ago
Annoying Probability Math Problem
RYang2   13
N Apr 18, 2025 by FabulousSpider24
I was working in my math textbook(not the AoPS one) when I came across this math problem:

Determine if the events are dependent or independent.
1. Drawing a red and a blue marble at the same time from a bag containing 6 red and 4 blue marbles
2.(omitted)

I thought it was independent, since the events happen at the same time, but the textbook answer said dependent.
Can someone help me understand(or prove the textbook wrong)?
13 replies
RYang2
Mar 14, 2018
FabulousSpider24
Apr 18, 2025
Annoying Probability Math Problem
G H J
G H BBookmark kLocked kLocked NReply
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
RYang2
1936 posts
#1 • 2 Y
Y by Adventure10, Mango247
I was working in my math textbook(not the AoPS one) when I came across this math problem:

Determine if the events are dependent or independent.
1. Drawing a red and a blue marble at the same time from a bag containing 6 red and 4 blue marbles
2.(omitted)

I thought it was independent, since the events happen at the same time, but the textbook answer said dependent.
Can someone help me understand(or prove the textbook wrong)?
This post has been edited 1 time. Last edited by RYang2, Mar 14, 2018, 5:10 PM
Reason: Too general subject
Z K Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
math_is_life_2004
1374 posts
#2 • 1 Y
Y by Adventure10
It’s dependent
Z K Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
RYang2
1936 posts
#3 • 1 Y
Y by Adventure10
Explain?
Z K Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
math_is_life_2004
1374 posts
#4 • 2 Y
Y by Adventure10, Mango247
Actually I think its independent what grade textbook you have?
Z K Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
brainpopper
1052 posts
#5 • 2 Y
Y by Adventure10, Mango247
Independent is only when they are replace or when the probability doesn't change, right? In #1, If we draw a blue marble first, the probability is 6/10 but the next red marble is 4/9
Z K Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
RYang2
1936 posts
#6 • 2 Y
Y by Adventure10, Mango247
Pre-Algebra Textbook
Z K Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
RYang2
1936 posts
#7 • 2 Y
Y by Adventure10, Mango247
And, the problem said at the same time, so there would be no "first" or "second"
Z K Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
math_is_life_2004
1374 posts
#8 • 2 Y
Y by Adventure10, Mango247
RYang2 wrote:
Pre-Algebra Textbook

Oh I haven’t done that for 2 years. After you memorized the law of cosine you kinda forget everything. #2ndquadraticequation
Z K Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
creeperhissboom
224 posts
#9 • 2 Y
Y by Adventure10, Mango247
It is dependant.

It is the same as taking one out at a time.
It is only independant if there is replacement.
Z K Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
A-Username
70 posts
#10 • 2 Y
Y by Adventure10, Mango247
RYang2 wrote:
I was working in my math textbook(not the AoPS one) when I came across this math problem:

Determine if the events are dependent or independent.
1. Drawing a red and a blue marble at the same time from a bag containing 6 red and 4 blue marbles
2.(omitted)

I thought it was independent, since the events happen at the same time, but the textbook answer said dependent.
Can someone help me understand(or prove the textbook wrong)?

@RYang2 Easy explanation for #1 is
Independent-Event 1 doesn't influence Event 2.
Dependent-Event 1 does influence Event 2.
Since this bag contains 6 red and 4 blues, there are 10 marbles in the bag. Now, we know that the color doesn't really matter because we know there is more than 1 for each color. Then we can determine which definition it fits better. First, we know it can't be dependent because if we take it at the same time, there is no sense of order and that the taking of the blue doesn't affect the number of reds there are and vice versa.
Z K Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
EthanNg6
35 posts
#11
Y by
It's probably dependent
Z K Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
Jaxman8
120 posts
#12
Y by
I think dependent, if you were to calculate the probabilities for blue first vs red first it’s the same
Z K Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
giratina3
512 posts
#13 • 1 Y
Y by EthanNg6
The answer is dependent. When you pick 2 marbles, the first pick affects the second one. Although you pick the two at the same time, the change in marble just occurs instantly, so it is still dependent (most average school textbook problem)
Z K Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
FabulousSpider24
141 posts
#14 • 1 Y
Y by EthanNg6
You can think about it like this: It is dependent because as soon as the first marble is taken, the number of marbles in the bag decreases and so the probability of picking a marble (either red or blue) will change immediately afterwards. .
Z K Y
N Quick Reply
G
H
=
a