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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
2026 AMC 8C
ChaitraliKA   9
N 12 minutes ago by RandomMathGuy500
You’ve never seen an AMC 8 quite like this…

We, ChaitraliKA and Aaronjudgeisgoat, present
THE 2026 AMC 8C

Context

This is a totally legit mock test that you can use to predict what your real AMC 8 score will be!
We created many high quality problems for this test, and put our blood, sweat, and tears into it (and if u dont take it we’ll put your blood into it as well). We GUARANTEE that when you take a look at the problems, you will be stunned by the sheer quality oozing out of them. We know this for certain as we got this exact reaction from every single newborn baby that volunteered to take this test. This mock is perfect, not just for people looking to ace the AMC 8 next year, but even for high schoolers.

[quote=ChaitraliKA]
This was my first time making a mock, I wanted to make it as realistic as possible. As a person who has never taken an AMC 8 before, I thoroughly researched the types of problems and the format before making this. After some deep analysing, I have come to the conclusion that our mock highly resembles an AMC 8 with a -100% margin of error. I personally enjoyed making this, and put my heart and soul into making the problems and writing out the solutions. There was a lot of collaboration and every question has approval from both of us. As the most respected Cringe Nerdy Mathematician in history, I can guarantee you that it's not only about the math, it's about the experience of taking it. Please scroll down and take the test now. Thank you. [/quote]

[quote=Aaronjudgeisgoat]
After writing a MATHCOUNTS mock, I figured I would try and take it a step further - create an AMC 8 mock. As a fellow person who has never taken an AMC 8 before, I knew there was work needed to be done before I could accurately create one. I thoroughly reviewed the rules for this test, as well as the format. I even made sure to make every single answer choice viable, simulating the silliable nature of the actual AMC 8. We reviewed every single question, answer and solution, and after cross-comparing it with actual MAA exams, I found that it's not 100% accurate to the exam, but 200% accurate. That's right, it's accurate and even more accurate. Overall, this was a very fun experience, creating my first AMC mock so that people in need of math problems have something to work on. I thank @ChaitraliKA for giving me the opportunity to problem write, and I had a very fun time collaborating with the Cringiest and Nerdiest Mathematician of them all. In conclusion, I implore you to click the link below and proceed with the test, as not only will you learn, you will have fun.
Thank you for your blood.
[/quote]

You have two options on how to take it: Google Docs or MathDash
Google Docs:
Problems
Please read the guidelines carefully, and submit your answers for grading to ChaitraliKA and Aaronjudgeisgoat through AoPS PMs. We will send you the solutions as well, once we have graded you.
MathDash:
https://mathdash.fly.dev/contest/2026amc8c
If you do it on MathDash, we will still send you your final score through AoPS PMs, due to some issues.

We expect to start grading on April 15.

The leaderboard will be updated on the MSM post.
Good luck :)!


Please don't get this locked again. I will be very sad if that happens, because this is my 1000th post :wow:. We put a lot of effort into this. If you're going to be a goody-two-shoes, just try to solve the legit problems and ignore the rest.

If you don't want to waste time, here are the legit problems that we would like you to try
9 replies
ChaitraliKA
Tuesday at 1:03 PM
RandomMathGuy500
12 minutes ago
2025 MATHCOUNTS State Hub
SirAppel   150
N 16 minutes ago by Soupboy0
Previous Years' "Hubs": (2022) (2023) (2024)Please Read

Now that it's April and we're allowed to discuss, and no one else has made this yet ...
[list=disc]
[*] CA: 43 (45 44 43 43 43 42 42 41 41 41)
[*] NJ: 43 (45 44 44 43 39 42 40 40 39 38) *
[*] NY: 42 (43 42 42 42 41 40)
[*] TX: 42 (43 43 43 42 42 40 40 38 38 38)
[*] MA: 41 (45 43 42 41)
[*] WA: 41 (41 45 42 41 41 41 41 41 41 40) *
[*] FL: 39 (42 41 40 39 38 37 37)
[*] IN: 39 (41 40 40 39 ?? 35)
[*] NC: 39 (42 42 41 39)
[*] IL: 38 (41 40 39 38 38 38)
[*] OR: 38 (44 41? 38 38)
[*] PA: 38 (41 40 40 38 38 37 36 36 34 34) *
[*] MD: 37 (43 39 39 37 37 37)
[*] CT: 36 (44 39? 38 36 34 34 34 34)
[*] MI: 36 (39 41 41 36 37 37 36 36 36 36) *
[*] MN: 36 (40 36 36 36 35 35 35 34)
[*] CO: 35 (41 37 37 35 35 35 ?? 31 31 30) *
[*] GA: 35 (38 37 36 35 34 34 34 34 34 33)
[*] OH: 35 (41 37 36 35)
[*] AR: 34 (46 45 35 34 33 31 31 31 29 29)
[*] WI: 34 (40 37 37 34 35 30 28 29 29 29) *
[*] NH: 31 (42 35 33 31 30)
[*] DE: 30 (34 33 32 30 30 29 28 27 26? 24)
[*] SC: 30 (33 33 31 30)
[*] IA: 29 (33 30 31 29 29 29 29 29 29 29 29 29) *
[*] RI: 29? (36 ?? ?? ??) *
[*] NE: 28 (34 30 28 28 27 27 26 26 25 25)
[*] SD: 22 (30 29 24 22 22 22 21 21 20 20)
[/list]

* means that CDR is official in that state.

Notes

For those asking about the removal of the tiers, I'd like to quote Jason himself:
[quote=peace09]
learn from my mistakes
[/quote]

Help contribute by sharing your state's cutoffs!
As per last year's guidelines, refrain from problem discussion until their official release on the MATHCOUNTS website.
150 replies
+3 w
SirAppel
Tuesday at 12:22 PM
Soupboy0
16 minutes ago
2025 MATHCOUNTS NATIONAL HUB
mathkiddus   15
N an hour ago by GarudS
Previous Years' ``Hubs":(2022) (2023) (2024) Please Read
Now that it's April and we can discuss mathcounts state...
[list=disc]
[*] NJ: 43 (45 44 44 43 39 42 40 40 39 38) *
[*] CA: 43 (45 44 43 43 43 42)
[*] TX: 42 (43 43 43 42 42 40)
[*] NY: 42 (43 42 42 42 41 40)
[*] WA: 41 (42 45 41 41 41 41 41 41 41 40) *
[*] MA: 41 (45 43 42 41 38 37 37)
[*] NC: 39 (42 42 41 39 38 37 36/37)
[*] FL: 39 (42 41 40 39 38 37 37 ??)
[*] IN: 39 (41 40 40 39)
[*] OH: 37? (41? 40? 38? 37?) *
[*] DE: 30 (34 33 32 30)
[*] CT: ?? (44 40/41 ?? ??)
[*] PA: ?? (41 ?? ?? ??) *
[*] UT: ?? (42 ?? ?? ??) *
[*] AR: ?? (45/46 ?? ?? ??)
[*] AL: ?? (?? ?? ?? ??)
[*] AK: ?? (?? ?? ?? ??)
[*] AZ: ?? (?? ?? ?? ??)
[*] CO: ?? (?? ?? ?? ??)
[*] GA: ?? (?? ?? ?? ??)
[*] HI: ?? (?? ?? ?? ??)
[*] ID: ?? (?? ?? ?? ??)
[*] IL: ?? (?? ?? ?? ??)
[*] IA: ?? (?? ?? ?? ??)
[*] KS: ?? (?? ?? ?? ??)
[*] KY: ?? (?? ?? ?? ??)
[*] LA: ?? (?? ?? ?? ??)
[*] ME: ?? (?? ?? ?? ??)
[*] MD: ?? (?? ?? ?? ??)
[*] MI: ?? (?? ?? ?? ??)
[*] MN: ?? (?? ?? ?? ??)
[*] MS: ?? (?? ?? ?? ??)
[*] MO: ?? (?? ?? ?? ??)
[*] MT: ?? (?? ?? ?? ??)
[*] NE: ?? (?? ?? ?? ??)
[*] NV: ?? (?? ?? ?? ??)
[*] NH: ?? (?? ?? ?? ??)
[*] NM: ?? (?? ?? ?? ??)
[*] ND: ?? (?? ?? ?? ??)
[*] OK: ?? (?? ?? ?? ??)
[*] OR: ?? (?? ?? ?? ??)
[*] RI: ?? (?? ?? ?? ??)
[*] SC: ?? (?? ?? ?? ??)
[*] SD: ?? (?? ?? ?? ??)
[*] TN: ?? (?? ?? ?? ??)
[*] VT: ?? (?? ?? ?? ??)
[*] VA: ?? (?? ?? ?? ??)
[*] WV: ?? (?? ?? ?? ??)
[*] WI: ?? (?? ?? ?? ??)
[*] WY: ?? (?? ?? ?? ??)
[*] PR: ?? (?? ?? ?? ??)
[*] VI: ?? (?? ?? ?? ??)
[*] DD: ?? (?? ?? ?? ??)
[*] SS: ?? (?? ?? ?? ??)
[*] GU: ?? (?? ?? ?? ??)
[*] DC: ?? (?? ?? ?? ??)
[/list]
Please help me fill in any missing details or correct any incorrect details. Note: any row with an * at the end means countdown is official in that state, to explain why some lower scores are ahead of higher ones.
The reason why there are no tiers and the chart is a lot less colorful than last year is because
[quote=peace09]learn from my mistakes[/quote]
15 replies
mathkiddus
Tuesday at 3:24 PM
GarudS
an hour ago
Famous geo configuration appears on the district MO
AndreiVila   5
N 2 hours ago by chirita.andrei
Source: Romanian District Olympiad 2025 10.4
Let $ABCDEF$ be a convex hexagon with $\angle A = \angle C=\angle E$ and $\angle B = \angle D=\angle F$.
[list=a]
[*] Prove that there is a unique point $P$ which is equidistant from sides $AB,CD$ and $EF$.
[*] If $G_1$ and $G_2$ are the centers of mass of $\triangle ACE$ and $\triangle BDF$, show that $\angle G_1PG_2=60^{\circ}$.
5 replies
AndreiVila
Mar 8, 2025
chirita.andrei
2 hours ago
Classic complex number geo
Ciobi_   1
N 2 hours ago by TestX01
Source: Romania NMO 2025 10.1
Let $M$ be a point in the plane, distinct from the vertices of $\triangle ABC$. Consider $N,P,Q$ the reflections of $M$ with respect to lines $AB, BC$ and $CA$, in this order.
a) Prove that $N, P ,Q$ are collinear if and only if $M$ lies on the circumcircle of $\triangle ABC$.
b) If $M$ does not lie on the circumcircle of $\triangle ABC$ and the centroids of triangles $\triangle ABC$ and $\triangle NPQ$ coincide, prove that $\triangle ABC$ is equilateral.
1 reply
Ciobi_
Yesterday at 12:56 PM
TestX01
2 hours ago
The greatest length of a sequence that satisfies a special condition
EmersonSoriano   0
2 hours ago
Source: 2018 Peru TST Cono Sur P9
Find the largest possible value of the positive integer $N$ given that there exist positive integers $a_1, a_2, \dots, a_N$ satisfying
$$ a_n = \sqrt{(a_{n-1})^2 + 2018 \, a_{n-2}}\:, \quad \text{for } n = 3,4,\dots,N. $$
0 replies
EmersonSoriano
2 hours ago
0 replies
Olympiad Geometry problem-second time posting
kjhgyuio   5
N 2 hours ago by kjhgyuio
Source: smo problem
In trapezium ABCD,AD is parallel to BC and points E and F are midpoints of AB and DC respectively. If
Area of AEFD/Area of EBCF =√3 + 1/3-√3 and the area of triangle ABD is √3 .find the area of trapezium ABCD
5 replies
kjhgyuio
Yesterday at 1:03 AM
kjhgyuio
2 hours ago
Summing the GCD of a number and the divisors of another.
EmersonSoriano   0
2 hours ago
Source: 2018 Peru TST Cono Sur P8
For each pair of positive integers $m$ and $n$, we define $f_m(n)$ as follows:
$$ f_m(n) = \gcd(n, d_1) + \gcd(n, d_2) + \cdots + \gcd(n, d_k), $$where $1 = d_1 < d_2 < \cdots < d_k = m$ are all the positive divisors of $m$. For example,
$f_4(6) = \gcd(6,1) + \gcd(6,2) + \gcd(6,4) = 5$.

$a)\:$ Find all positive integers $n$ such that $f_{2017}(n) = f_n(2017)$.

$b)\:$ Find all positive integers $n$ such that $f_6(n) = f_n(6)$.
0 replies
EmersonSoriano
2 hours ago
0 replies
Sum of whose elements is divisible by p
nntrkien   42
N 2 hours ago by cubres
Source: IMO 1995, Problem 6, Day 2, IMO Shortlist 1995, N6
Let $ p$ be an odd prime number. How many $ p$-element subsets $ A$ of $ \{1,2,\dots,2p\}$ are there, the sum of whose elements is divisible by $ p$?
42 replies
nntrkien
Aug 8, 2004
cubres
2 hours ago
kind of well known?
dotscom26   3
N 2 hours ago by Svenskerhaor
Source: MBL
Let $ y_1, y_2, ..., y_{2025}$ be real numbers satisfying
$
y_1^2 + y_2^2 + \cdots + y_{2025}^2 = 1.
$
Find the maximum value of
$
|y_1 - y_2| + |y_2 - y_3| + \cdots + |y_{2025} - y_1|.
$

I have seen many problems with the same structure, Id really appreciate if someone could explain which approach is suitable here
3 replies
dotscom26
Tuesday at 4:11 AM
Svenskerhaor
2 hours ago
Locus of a point on the side of a square
EmersonSoriano   0
2 hours ago
Source: 2018 Peru TST Cono Sur P7
Let $ABCD$ be a fixed square and $K$ a variable point on segment $AD$. The square $KLMN$ is constructed such that $B$ is on segment $LM$ and $C$ is on segment $MN$. Let $T$ be the intersection point of lines $LA$ and $ND$. Find the locus of $T$ as $K$ varies along segment $AD$.
0 replies
EmersonSoriano
2 hours ago
0 replies
Chess queens on a cylindrical board
EmersonSoriano   0
2 hours ago
Source: 2018 Peru TST Cono Sur P6
Let $n$ be a positive integer. In an $n \times n$ board, two opposite sides have been joined, forming a cylinder. Determine whether it is possible to place $n$ queens on the board such that no two threaten each other when:

$a)\:$ $n=14$.

$b)\:$ $n=15$.
0 replies
EmersonSoriano
2 hours ago
0 replies
9 Have you participated in the MATHCOUNTS competition?
aadimathgenius9   17
N 2 hours ago by Spacepandamath13
Have you participated in the MATHCOUNTS competition before?
17 replies
aadimathgenius9
Jan 1, 2025
Spacepandamath13
2 hours ago
2015 solutions for quotient function!
raxu   48
N 2 hours ago by zuat.e
Source: TSTST 2015 Problem 5
Let $\varphi(n)$ denote the number of positive integers less than $n$ that are relatively prime to $n$. Prove that there exists a positive integer $m$ for which the equation $\varphi(n)=m$ has at least $2015$ solutions in $n$.

Proposed by Iurie Boreico
48 replies
raxu
Jun 26, 2015
zuat.e
2 hours ago
Mathcounts Target Resources
sadas123   3
N Mar 29, 2025 by Andyluo
I was wondering what I could use to practice for Mathcount Target rounds because my sprint is normally 23-25+ (Depending on the level: This is for Chapter, but some times for states) but my target is normally 8-10 (Depending on the level: This is normally for states and some time Nats) and I want that to go up to 12-14 So I was wondering what are some good resources to build that problem solving knowledge for target, and some resources that will help me learn the complex problems on there mostly for Geometry and Algebra.
3 replies
sadas123
Mar 29, 2025
Andyluo
Mar 29, 2025
Mathcounts Target Resources
G H J
G H BBookmark kLocked kLocked NReply
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sadas123
1105 posts
#1
Y by
I was wondering what I could use to practice for Mathcount Target rounds because my sprint is normally 23-25+ (Depending on the level: This is for Chapter, but some times for states) but my target is normally 8-10 (Depending on the level: This is normally for states and some time Nats) and I want that to go up to 12-14 So I was wondering what are some good resources to build that problem solving knowledge for target, and some resources that will help me learn the complex problems on there mostly for Geometry and Algebra.
This post has been edited 1 time. Last edited by sadas123, Mar 29, 2025, 8:17 PM
Z K Y
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Inaaya
215 posts
#2
Y by
what level is this?
Z K Y
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sadas123
1105 posts
#3
Y by
Inaaya wrote:
what level is this?

oh.. I just edited this and added it.
Z K Y
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Andyluo
889 posts
#4
Y by
For MATHCOUNTS target, the main importance is practicing harder tests, and doing harder contests such as the AMC 10/AIME with longer times.

Sprint I've realized that the theory is usually really easy, (but at some level you have to practice it) the main emphasis is not sillying and going insanely fast
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