Art of Problem Solving
AoPS Online AoPS Online
Math texts, online classes, and more
for students in grades 5-12.
Visit AoPS Online ‚
Books for Grades 5-12 Online Courses
Beast Academy Beast Academy
Engaging math books and online learning
for students ages 6-13.
Visit Beast Academy ‚
Books for Ages 6-13 Beast Academy Online
AoPS Academy AoPS Academy
Small live classes for advanced math
and language arts learners in grades 1-12.
Visit AoPS Academy ‚
Find a Physical Campus Visit the Virtual Campus

Stay ahead of learning milestones! Enroll in a class over the summer!
No tags match your search
M
G
Topic
First Poster
Last Poster
H
k a April Highlights and 2025 AoPS Online Class Information
jlacosta   0
Apr 2, 2025
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.

Introductory: Grades 5-10

Prealgebra 1 Self-Paced

Prealgebra 1
Sunday, Apr 13 - Aug 10
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
Sunday, Apr 13 - Aug 10
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
Monday, Apr 7 - Jul 28
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
Wednesday, Apr 16 - Jul 2
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
Thursday, Apr 17 - Jul 3
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
Wednesday, Apr 16 - Jul 30
Tuesday, May 6 - Aug 19
Wednesday, Jun 4 - Sep 17
Sunday, Jun 22 - Oct 19
Friday, Jul 18 - Nov 14

Introduction to Geometry
Wednesday, Apr 23 - Oct 1
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

Intermediate: Grades 8-12

Intermediate Algebra
Monday, Apr 21 - Oct 13
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
Friday, Apr 11 - Jun 27
Sunday, Jun 1 - Aug 24
Wednesday, Jun 18 - Sep 3

Precalculus
Wednesday, Apr 9 - Sep 3
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
Wednesday, Apr 16 - Jul 2
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
Friday, Apr 11 - Jun 27
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

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
Sat & Sun, Apr 26 - Apr 27 (4:00 - 7:00 pm ET/1:00 - 4:00pm PT)
Mon, Tue, Wed & Thurs, Jun 23 - Jun 26 (meets every day of the week!)
0 replies
jlacosta
Apr 2, 2025
0 replies
J
H
Coaxal Circles
fattypiggy123   29
N 4 minutes ago by sttsmet
Source: China TSTST Test 2 Day 1 Q3
Let $ABCD$ be a quadrilateral and let $l$ be a line. Let $l$ intersect the lines $AB,CD,BC,DA,AC,BD$ at points $X,X',Y,Y',Z,Z'$ respectively. Given that these six points on $l$ are in the order $X,Y,Z,X',Y',Z'$, show that the circles with diameter $XX',YY',ZZ'$ are coaxal.
29 replies
fattypiggy123
Mar 13, 2017
sttsmet
4 minutes ago
J
H
q(x) to be the product of all primes less than p(x)
orl   16
N 15 minutes ago by Maximilian113
Source: IMO Shortlist 1995, S3
For an integer $x \geq 1$, let $p(x)$ be the least prime that does not divide $x$, and define $q(x)$ to be the product of all primes less than $p(x)$. In particular, $p(1) = 2.$ For $x$ having $p(x) = 2$, define $q(x) = 1$. Consider the sequence $x_0, x_1, x_2, \ldots$ defined by $x_0 = 1$ and \[ x_{n+1} = \frac{x_n p(x_n)}{q(x_n)} \] for $n \geq 0$. Find all $n$ such that $x_n = 1995$.
16 replies
1 viewing
orl
Aug 10, 2008
Maximilian113
15 minutes ago
J
H
inequalities
pennypc123456789   1
N 20 minutes ago by KhuongTrang
If $a,b,c$ are positive real numbers, then
$$ \frac{a + b}{a + 7b + c} + \dfrac{b + c}{b + 7c + a}+\dfrac{c + a}{c + 7a + b} \geq \dfrac{2}{3}$$
we can generalize this problem
1 reply
pennypc123456789
43 minutes ago
KhuongTrang
20 minutes ago
J
H
Inspired by JK1603JK
sqing   0
25 minutes ago
Source: Own
Let $ a,b,c\geq 0 $ and $ ab+bc+ca=3. $ Prove that
$$ (a+b+c-3)(12-5abc)\ge 2(a-b)(b-c)(a-c)$$$$6(a+b+c-3)(5-2abc)\ge 5(a-b)(b-c)(a-c)$$$$2(a+b+c-3)(9-5abc)\ge 3(a-b)(b-c)(a-c)$$$$3(a+b+c-3)(14-5abc)\ge 7(a-b)(b-c)(a-c)$$
0 replies
1 viewing
sqing
25 minutes ago
0 replies
J
No more topics!
H
J
H
567 Nice And Hard Inequalities
Lionel Messi   9
N Jul 25, 2016 by Dilshodbek
This is ebook 567 Nice And Hard of author Nguyen Duy Tung.
It was written by a problem or that I find most beautiful and synthesized in mathlinks.
Because for some reason that is not completely Messi_ndt is insufficient documentation to be put up but also let you read.
Still some unfinished space and missing some parts that I intend to do.
Anyway this is the heart of Messi_ndt in a long time.
Dowdload check readers.
You can dowload here.
Nguyễn Duy Tùng.
9 replies
Lionel Messi
Jan 13, 2011
Dilshodbek
Jul 25, 2016
J
567 Nice And Hard Inequalities
G H J
Reveal topic tags
inequalities
Problem Sets
L
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.
Lionel Messi
174 posts
Lionel Messi
#1 h  Jan 13, 2011, 6:23 AM • 21 Y
Y by Amir Hossein, Potla, sindennisz, eddy13579, ivanbart-15, TheBottle, sdsert, Pinphong, War-Hammer, minimario, Riju, claserken, fjm30, hansduran0123, Adventure10, and 6 other users
This is ebook 567 Nice And Hard of author Nguyen Duy Tung.
It was written by a problem or that I find most beautiful and synthesized in mathlinks.
Because for some reason that is not completely Messi_ndt is insufficient documentation to be put up but also let you read.
Still some unfinished space and missing some parts that I intend to do.
Anyway this is the heart of Messi_ndt in a long time.
Dowdload check readers.
You can dowload here.
Nguyễn Duy Tùng.
Attachments:
567 Nice And Hard Inequality.pdf (1435kb)
Z K Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
mcrasher
1764 posts
mcrasher
#2 h  Jan 13, 2011, 9:44 AM • 2 Y
Y by Adventure10, Mango247
thanks for the link.. :)
Z K Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
Amir Hossein
5452 posts
Amir Hossein
#3 h  Jan 13, 2011, 12:14 PM • 2 Y
Y by Adventure10, Mango247
Thanks! That's great! :)
Z K Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
litongyang
387 posts
litongyang
#4 h  Jan 14, 2011, 6:57 AM • 1 Y
Y by Adventure10
Yes, it's indeed a very very nice book. :lol:
Z K Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
red3
905 posts
red3
#5 h  Feb 12, 2011, 4:37 AM • 3 Y
Y by Adventure10, Mango247, and 1 other user
$\sum \frac{1}{a^2+bc} >\frac{3\sum a^2}{\sum a^3b+ab^3}>\frac{12}{(\sum a)^2} $



this is nice and true ,but the first one haven't been prove in the book

i expand it to $\sum (a-b)^2(2a^4c^2+2b^4c^2+2a^2b^2c^2+2(a^2+b^2)abc^2-a^4bc-ab^4c)>0$

it is true ,but proof is not good


and the second one can reduce to


$\sum a^4+2a^2b^2+2a^2bc>2\sum a^3b+ab^3 $

it is true by EMV ,but these prood not nice ,i want to see a better proofs.......
Z K Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
red3
905 posts
red3
#6 h  Feb 17, 2011, 11:15 AM • 3 Y
Y by Adventure10, Mango247, and 1 other user
ok , 1. the solution of p234 has some problem ,also to


p249 ,p266,p279 it is hard to get the result

p263 has no solution


there are many nice solutions in this book
Z K Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
Reincarnating
1 post
Reincarnating
#7 h  May 26, 2013, 8:57 AM • 2 Y
Y by Adventure10, Mango247
Thanks for the link,it's really a great resource.
Z K Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
War-Hammer
670 posts
War-Hammer
#8 h  May 26, 2013, 5:44 PM • 1 Y
Y by Adventure10
Hi ;

Thanks , Nice and useful .

Best Regard
Z K Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
shinichiman
3212 posts
shinichiman
#9 h  Jul 6, 2013, 3:43 AM • 3 Y
Y by Dilshodbek, Adventure10, Mango247
Nice!!
Thank you very much.
Z K Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
Dilshodbek
115 posts
Dilshodbek
#10 h  Jul 25, 2016, 7:55 PM • 2 Y
Y by Adventure10, Mango247
Thank a lot
Z K Y
N Quick Reply
G
H
=
a