G
Topic
First Poster
Last Poster
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.

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
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
2025 MATHCOUNTS State Hub
SirAppel   194
N a minute 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.
194 replies
SirAppel
Tuesday at 12:22 PM
Soupboy0
a minute ago
9 MATHCOUNTS STATE difficulty
Eddie_tiger   52
N 9 minutes ago by orangebear
I personally thought the problems were much easier than last year, but I didn't really improve as much as I would of liked to improve.
52 replies
Eddie_tiger
Tuesday at 1:13 PM
orangebear
9 minutes ago
2026 AMC 8C
ChaitraliKA   15
N 21 minutes ago by jkim0656
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
15 replies
ChaitraliKA
Tuesday at 1:03 PM
jkim0656
21 minutes ago
Thanks u!
Ruji2018252   5
N 2 hours ago by Sadigly
Find all $f:\mathbb{R}\to\mathbb{R}$ and
\[ f(x+y)+f(x^2+f(y))=f(f(x))^2+f(x)+f(y)+y,\forall x,y\in\mathbb{R}\]
5 replies
Ruji2018252
Mar 26, 2025
Sadigly
2 hours ago
2025 MATHCOUNTS NATIONAL HUB
mathkiddus   15
N 2 hours 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
2 hours ago
Famous geo configuration appears on the district MO
AndreiVila   5
N 3 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
3 hours ago
Classic complex number geo
Ciobi_   1
N 3 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
3 hours ago
The greatest length of a sequence that satisfies a special condition
EmersonSoriano   0
3 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
3 hours ago
0 replies
Olympiad Geometry problem-second time posting
kjhgyuio   5
N 3 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
3 hours ago
Summing the GCD of a number and the divisors of another.
EmersonSoriano   0
3 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
3 hours ago
0 replies
Sum of whose elements is divisible by p
nntrkien   42
N 3 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
3 hours ago
kind of well known?
dotscom26   3
N 3 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
3 hours ago
Locus of a point on the side of a square
EmersonSoriano   0
3 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
3 hours ago
0 replies
Chess queens on a cylindrical board
EmersonSoriano   0
3 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
3 hours ago
0 replies
k Mathcounts State Sprint Scores
kp34912   29
N Mar 31, 2025 by TiguhBabeHwo
I am practicing previous years' MathCount papers, but they seem to get progressively harder each year.

So, for those of you who scored well in Mathcounts, how many sprint questions are/were you able to do in State/Nationals?

I want to get a sense of where I stand.

Thanks in advance!
29 replies
kp34912
Mar 27, 2025
TiguhBabeHwo
Mar 31, 2025
Mathcounts State Sprint Scores
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.
kp34912
3 posts
#1
Y by
I am practicing previous years' MathCount papers, but they seem to get progressively harder each year.

So, for those of you who scored well in Mathcounts, how many sprint questions are/were you able to do in State/Nationals?

I want to get a sense of where I stand.

Thanks in advance!
This post has been edited 1 time. Last edited by kp34912, Mar 27, 2025, 9:27 AM
Reason: edited
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
Bummer12345
119 posts
#2
Y by
wait do you mean problems you were able to do or you got correct

because i sillied around 9 points at 2024 nats (from 33 to 24)
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
Hanruz
16 posts
#3 • 2 Y
Y by MathPerson12321, kp34912
I believe more recent tests are more difficult. For earlier years like 2000-2015, I mock 44-46(because of sillies). For later years, I mock 34-39. (For nationals)
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
kp34912
3 posts
#5
Y by
Thanks guys.....those are some really great scores!

Can you give some pointers as how to improve the speed and accuracy? I am kinda hitting a stone wall....getting frustrating
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
ethan2011
255 posts
#6
Y by
kp34912 wrote:
I am practicing previous years' MathCount papers, but they seem to get progressively harder each year.

So, for those of you who scored well in Mathcounts, how many sprint questions are/were you able to do in State/Nationals?

I want to get a sense of where I stand.

Thanks in advance!

I did 20 at nats, 23 at state last year
but I think I improved this year :D
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
fruitmonster97
2430 posts
#7
Y by
@above what aintnoway you had a 23 states

personally had 36 states and 29 nats last year, if i could actually do sprint my scores would be much higher :sigh:
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
BS2012
967 posts
#8 • 1 Y
Y by MathPerson12321
sillied like 7 times in nats sprint but guessed one right
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
DhruvJha
802 posts
#9
Y by
fruitmonster97 wrote:
@above what aintnoway you had a 23 states

personally had 36 states and 29 nats last year, if i could actually do sprint my scores would be much higher :sigh:

no he's talking about his sprint score. 23 state sprint. 20 nats sprint

I went from 15 sprint state to 15 sprint nats lock in

however target 2/8

got me a 19 total score/46 which was like 125th is i dont remmeber exactly
This post has been edited 3 times. Last edited by DhruvJha, Mar 27, 2025, 7:10 PM
Reason: j
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
Soupboy0
257 posts
#10
Y by
bro how do you guys get so smart :( i mock ~30 total on nats from after 2020 :( :( :(
This post has been edited 1 time. Last edited by Soupboy0, Mar 27, 2025, 7:09 PM
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
DhruvJha
802 posts
#11
Y by
Soupboy0 wrote:
bro how do you guys get so smart :( i mock ~30 total on nats from after 2020 :( :( :(


i got 15 on state sprint last year and 19 on nats total. BS2012 is the smart orz cdr qual

I went from 35 chapter 25 states 19 nats
This post has been edited 1 time. Last edited by DhruvJha, Mar 27, 2025, 7:11 PM
Reason: swwssw
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
ethan2011
255 posts
#12
Y by
fruitmonster97 wrote:
@above what aintnoway you had a 23 states

personally had 36 states and 29 nats last year, if i could actually do sprint my scores would be much higher :sigh:

rbo he was asking for just sprint not sprint+2*target :skull:
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
Soupboy0
257 posts
#13
Y by
i mock ~20 on sprint :skull: and then i sell target :more skull:
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
DhruvJha
802 posts
#14
Y by
ethan2011 wrote:
fruitmonster97 wrote:
@above what aintnoway you had a 23 states

personally had 36 states and 29 nats last year, if i could actually do sprint my scores would be much higher :sigh:

rbo he was asking for just sprint not sprint+2*target :skull:


can you explain what rbo means idk all this aops slang
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
fruitmonster97
2430 posts
#15
Y by
oh whoops

22 state and 17 nats im target main(14 and 12)
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
Soupboy0
257 posts
#16
Y by
i suck at target are there any tips to get better
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
DhruvJha
802 posts
#17
Y by
Soupboy0 wrote:
i suck at target are there any tips to get better

on each page there are light problems(odd numbered problems) and then there are harder probs(easy probs). So plan of action is to do the light ones first in like 2 mins and use the other 4 mins for the hard one
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
Soupboy0
257 posts
#18
Y by
yeah but how do u do the hard ones
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
Mathematicalprodigy37
11 posts
#19
Y by
Chapter: 23 on sprint and 12 on target(2025) (we don't talk about my silly on #4) and a combined score of 35 in 2024
[redacted] an 18 combined score in 2024
Nationals: mocked 2018 and got a 35(23 on sprint and 12 on target (should I be concerned???))
This post has been edited 2 times. Last edited by Mathematicalprodigy37, Mar 28, 2025, 8:29 PM
Reason: no discussion allowed for 2025 state
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
DhruvJha
802 posts
#20 • 1 Y
Y by Mathematicalprodigy37
Mathematicalprodigy37 wrote:
Chapter: 23 on sprint and 12 on target(we don't talk about my silly on #4)
State: 21 on sprint and 14 on target
Nationals: mocked 2018 and got a 35(23 on sprint and 12 on target (should I be concerned???))

no with that score distrib you would land yourself 6th in nats written wise
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
Hanruz
16 posts
#21
Y by
Soupboy0 wrote:
bro how do you guys get so smart :( i mock ~30 total on nats from after 2020 :( :( :(

My advice is to just do a lot of mocks. Last year, I got a 29 on the state round and didn't even make top 12(NY). This year I did every past National and State round from 2000-2023. Even though there were a couple of people better than me, I still got first because I did way more practice tests than them.
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
fruitmonster97
2430 posts
#22
Y by
Soupboy0 wrote:
bro how do you guys get so smart :( i mock ~30 total on nats from after 2020 :( :( :(

30 nats this past year was top 35-ish. That is very good.
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
iwastedmyusername
60 posts
#23
Y by
how do you get nats tests from after 2017? i cant find them online
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
BS2012
967 posts
#24
Y by
iwastedmyusername wrote:
how do you get nats tests from after 2017? i cant find them online

you buy them or go to that years nats competition
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
Andyluo
891 posts
#25
Y by
BS2012 wrote:
iwastedmyusername wrote:
how do you get nats tests from after 2017? i cant find them online

you buy them or go to that years nats competition

or you know a guy who knows a guy who knows a guy who knows a guy who knows a guy who gives you all 2018-2024 tests in a nice pdf. :)
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
derekwang2048
1203 posts
#28
Y by
@above + @2above plz edit posts so that no one sees
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
programjames1
3033 posts
#29
Y by
Soupboy0 wrote:
i suck at target are there any tips to get better

Solve AIME problems. Once you can regularly solve problems 1–10, give yourself five minutes per problem.
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
ethan2011
255 posts
#30
Y by
programjames1 wrote:
Soupboy0 wrote:
i suck at target are there any tips to get better

Solve AIME problems. Once you can regularly solve problems 1–10, give yourself five minutes per problem.

*Solve AIME problems using a calculator. It's so nice to have one, especially for all the people that missed JMO because of arithmetic errors.
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
nmlikesmath
482 posts
#32 • 1 Y
Y by Exponent11
i mock around 20s on state sprint rounds
2017 and 2023 were hard, 2019 and 2022 were relatively easy compared to the other ones
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
hashbrown2009
152 posts
#33 • 1 Y
Y by Exponent11
Meh, 6th grade got 36 at states, 24+12. No nats qual rip
7th grade, 39 states 25+14 Nats got 22 :/
8th grade: 41 states 27+14 Nats got like 30ish something

To practice State Sprint, do AMC10 and AMC12 and time yourself in terms of MathCounts time. For last 5ish u can use AIME problems.
Target, same as above except allow a calculator and make the problems harder.
This post has been edited 1 time. Last edited by hashbrown2009, Mar 30, 2025, 11:08 PM
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
TiguhBabeHwo
452 posts
#34 • 1 Y
Y by Exponent11
6th: 19, no nats badge
7th: 24 state 21 natsbadge
8th: 25 state (omg) 22 natsbadge
Z Y
G
H
=
a