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k a June Highlights and 2025 AoPS Online Class Information
jlacosta   0
3 hours ago
Congratulations to all the mathletes who competed at National MATHCOUNTS! If you missed the exciting Countdown Round, you can watch the video at this link. Are you interested in training for MATHCOUNTS or AMC 10 contests? How would you like to train for these math competitions in half the time? We have accelerated sections which meet twice per week instead of once starting on July 8th (7:30pm ET). These sections fill quickly so enroll today!

[list][*]MATHCOUNTS/AMC 8 Basics
[*]MATHCOUNTS/AMC 8 Advanced
[*]AMC 10 Problem Series[/list]
For those interested in Olympiad level training in math, computer science, physics, and chemistry, be sure to enroll in our WOOT courses before August 19th to take advantage of early bird pricing!

Summer camps are starting this 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 a transformative 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][*]June 5th, Thursday, 7:30pm ET: Open Discussion with Ben Kornell and Andrew Sutherland, Art of Problem Solving's incoming CEO Ben Kornell and CPO Andrew Sutherland host an Ask Me Anything-style chat. Come ask your questions and get to know our incoming CEO & CPO!
[*]June 9th, Monday, 7:30pm ET, Game Jam: Operation Shuffle!, Come join us to play our second round of Operation Shuffle! If you enjoy number sense, logic, and a healthy dose of luck, this is the game for you. No specific math background is required; all are welcome.[/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
3 hours ago
0 replies
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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
J
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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
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PAGE NOT SCROLLING DOWN ALL THE WAY; GETS STUCK 1.5 POSTS BEFORE THREAD END
CurlyFalcon55   5
N 13 minutes ago by SlyOwl45
Summary of the problem:
Whenever I push the big, top right "Reply" button– NOT THE SMALL LITTLE "QUICK REPLY" BAR ON THE BOTTOM, and reply, I can't scroll down all the way to the bottom of the thread that I just posted in. Sometimes, very rarely though, I doesn't scroll down all the way when I push the "Quick Reply" bar.


-----Page URL:
Anywhere in the "Introduction to Number Theory" forum in AoPS


-----Steps to reproduce:

1. Go to the link above.

2. Click any thread or create a new one.

3. Click the "Reply" button, not the quick reply bar.

4. Type a reply.

5. Push the "Submit" button.

6. Try to scroll down. if you’re lucky, the problem will reproduce.

-----Expected behavior:
To scroll all the way down.


-----Frequency:
Almost every time I push the big "Reply" button, sometimes (but rarely) when I push the "Quick Reply" bar.


-----Operating system(s):
macOS Sequoia 15.4.1


-----Browser(s), including version:
Chrome, (I don't know what version)


-----Additional information:
-It rarely does it in the "Quick Reply" bar.
-It almost always does it in the big "Reply" button on the top right.


-----Can anyone reproduce?
5 replies
CurlyFalcon55
Yesterday at 11:23 PM
SlyOwl45
13 minutes ago
J
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Parallel lines on a rhombus
buratinogigle   1
N 2 hours ago by Giabach298
Source: Own, Entrance Exam for Grade 10 Admission, HSGS 2025
Given the rhombus $ABCD$ with its incircle $\omega$. Let $E$ and $F$ be the points of tangency of $\omega$ with $AB$ and $AC$ respectively. On the edges $CB$ and $CD$, take points $G$ and $H$ such that $GH$ is tangent to $\omega$ at $P$. Suppose $Q$ is the intersection point of the lines $EG$ and $FH$. Prove that two lines $AP$ and $CQ$ are parallel or coincide.
1 reply
buratinogigle
3 hours ago
Giabach298
2 hours ago
J
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Orthocenter lies on circumcircle
whatshisbucket   90
N 2 hours ago by bjump
Source: 2017 ELMO #2
Let $ABC$ be a triangle with orthocenter $H,$ and let $M$ be the midpoint of $\overline{BC}.$ Suppose that $P$ and $Q$ are distinct points on the circle with diameter $\overline{AH},$ different from $A,$ such that $M$ lies on line $PQ.$ Prove that the orthocenter of $\triangle APQ$ lies on the circumcircle of $\triangle ABC.$

Proposed by Michael Ren
90 replies
whatshisbucket
Jun 26, 2017
bjump
2 hours ago
J
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Polish MO Finals 2014, Problem 4
j___d   3
N 2 hours ago by ariopro1387
Source: Polish MO Finals 2014
Denote the set of positive rational numbers by $\mathbb{Q}_{+}$. Find all functions $f: \mathbb{Q}_{+}\rightarrow \mathbb{Q}_{+}$ that satisfy
$$\underbrace{f(f(f(\dots f(f}_{n}(q))\dots )))=f(nq)$$for all integers $n\ge 1$ and rational numbers $q>0$.
3 replies
+1 w
j___d
Jul 27, 2016
ariopro1387
2 hours ago
J
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S(an) greater than S(n)
ilovemath0402   1
N 3 hours ago by ilovemath0402
Source: Inspired by an old result
Find all positive integer $n$ such that $S(an)\ge S(n) \quad \forall a \in \mathbb{Z}^{+}$ ($S(n)$ is sum of digit of $n$ in base 10)
P/s: Original problem
1 reply
ilovemath0402
3 hours ago
ilovemath0402
3 hours ago
J
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Hagge-like circles, Jerabek hyperbola, Lemoine cubic
kosmonauten3114   0
3 hours ago
Source: My own
Let $\triangle{ABC}$ be a scalene oblique triangle with circumcenter $O$ and orthocenter $H$, and $P$ ($\neq \text{X(3), X(4)}$, $\notin \odot(ABC)$) a point in the plane.
Let $\triangle{A_1B_1C_1}$, $\triangle{A_2B_2C_2}$ be the circumcevian triangles of $O$, $P$, respectively.
Let $\triangle{P_AP_BP_C}$ be the pedal triangle of $P$ with respect to $\triangle{ABC}$.
Let $A_1'$ be the reflection in $P_A$ of $A_1$. Define $B_1'$, $C_1'$ cyclically.
Let $A_2'$ be the reflection in $P_A$ of $A_2$. Define $B_2'$, $C_2'$ cyclically.
Let $O_1$, $O_2$ be the circumcenters of $\triangle{A_1'B_1'C_1'}$, $\triangle{A_2'B_2'C_2'}$, respectively.

Prove that:
1) $P$, $O_1$, $O_2$ are collinear if and only if $P$ lies on the Jerabek hyperbola of $\triangle{ABC}$.
2) $H$, $O_1$, $O_2$ are collinear if and only if $P$ lies on the Lemoine cubic (= $\text{K009}$) of $\triangle{ABC}$.
0 replies
kosmonauten3114
3 hours ago
0 replies
J
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Incenter perpendiculars and angle congruences
math154   84
N 3 hours ago by zuat.e
Source: ELMO Shortlist 2012, G3
$ABC$ is a triangle with incenter $I$. The foot of the perpendicular from $I$ to $BC$ is $D$, and the foot of the perpendicular from $I$ to $AD$ is $P$. Prove that $\angle BPD = \angle DPC$.

Alex Zhu.
84 replies
math154
Jul 2, 2012
zuat.e
3 hours ago
J
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Tangency of circles with "135 degree" angles
Shayan-TayefehIR   4
N 3 hours ago by Mysteriouxxx
Source: Iran Team selection test 2024 - P12
For a triangle $\triangle ABC$ with an obtuse angle $\angle A$ , let $E , F$ be feet of altitudes from $B , C$ on sides $AC , AB$ respectively. The tangents from $B , C$ to circumcircle of triangle $\triangle ABC$ intersect line $EF$ at points $K , L$ respectively and we know that $\angle CLB=135$. Point $R$ lies on segment $BK$ in such a way that $KR=KL$ and let $S$ be a point on line $BK$ such that $K$ is between $B , S$ and $\angle BLS=135$. Prove that the circle with diameter $RS$ is tangent to circumcircle of triangle $\triangle ABC$.

Proposed by Mehran Talaei
4 replies
Shayan-TayefehIR
May 19, 2024
Mysteriouxxx
3 hours ago
J
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FE inequality from Iran
mojyla222   4
N 3 hours ago by shanelin-sigma
Source: Iran 2025 second round P5
Find all functions $f:\mathbb{R}^+ \to \mathbb{R}$ such that for all $x,y,z>0$
$$ 3(x^3+y^3+z^3)\geq f(x+y+z)\cdot f(xy+yz+xz) \geq (x+y+z)(xy+yz+xz). $$
4 replies
mojyla222
Apr 19, 2025
shanelin-sigma
3 hours ago
J
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Line bisects a segment
buratinogigle   1
N 3 hours ago by cj13609517288
Source: Own, Entrance Exam for Grade 10 Admission, HSGS 2025
Let $ABC$ be a triangle with $AB = AC$. A circle $(O)$ is tangent to sides $AC$ and $AB$, and $O$ is the midpoint of $BC$. Points $E$ and $F$ lie on sides $AC$ and $AB$, respectively, such that segment $EF$ is tangent to circle $(O)$ at point $P$. Let $H$ and $K$ be the orthocenters of triangles $OBF$ and $OCE$, respectively. Prove that line $OP$ bisects segment $HK$.
1 reply
buratinogigle
3 hours ago
cj13609517288
3 hours ago
J
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Removing Numbers On A Blackboard
Kezer   5
N 3 hours ago by MathematicalArceus
Source: Bundeswettbewerb Mathematik 2017, Round 1 - #1
The numbers $1,2,3,\dots,2017$ are on the blackboard. Amelie and Boris take turns removing one of those until only two numbers remain on the board. Amelie starts. If the sum of the last two numbers is divisible by $8$, then Amelie wins. Else Boris wins. Who can force a victory?
5 replies
Kezer
Aug 7, 2017
MathematicalArceus
3 hours ago
J
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what??????????????????????
Iced_Coffee   10
N 4 hours ago by CurlyFalcon55
my "my topics" symbol (the little person looking button) and my "bookmarked topics" symbol keep randomly changing to different symbols!!!!!!!! What is happening? the 'my topics' one changed so it looked like it had a gear and a music note and I don't even know what the other one was. this has been happening for two or three days now is it happening to anyone else? please help! :what?:
10 replies
Iced_Coffee
Apr 11, 2025
CurlyFalcon55
4 hours ago
J
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Post Times are Wrong
CurlyFalcon55   7
N 5 hours ago by CurlyFalcon55
Summary of the problem:
Every time a new post is posted, instead of the time it was posted at, it says "in 41 minutes" or "in an hour" or something like that. I was wondering, is that normal? I happens pretty regularly, though not all the time.

Page URL: Anywhere in the "Introduction to Number Theory" forum in AoPS

Steps to reproduce:
1.Go to the link above.
2.a.Click on any thread or b.just create a new thread.
3.If a., and if someone just posted, the bug might reproduce, and if you post, the problem might reproduce.
If b., then post something, and you might be lucky to see it reproduce.

Expected behavior:
Show the time it's been posted.

Frequency:
Pretty often.

Operating system:
macOS Sequoia 15.4.1

Browsers, including version:
Chrome, (I don't know what version)

Additional information:
This is hard to catch. It just sneaks up on you.

Does anyone else have the same problem? :help:
7 replies
CurlyFalcon55
Yesterday at 10:30 PM
CurlyFalcon55
5 hours ago
J
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Hide tag workaround
char0221   13
N 5 hours ago by CurlyFalcon55
Summary of the problem: When quoting a tip tag, hovering over it causes a glitch where the tip tag's inner contents are "stuck" below the quotes.
Page URL: Any community message boards.
Steps to reproduce:
1. Create a message.
2. Insert a quote.
3. Inside the quote, put a tip tag.
4. Submit/preview, then hover over the tip tag.
Expected behavior: Tip tag does not stay when mouse is removed.
Frequency: 100%
Operating system(s): macOS Sequoia
Browser(s), including version: Safari 18.4
Additional information:
IMAGE
Also, make sure that the quote+tip is last.
[quote=char0221]
Try to close me!
[/quote]
13 replies
char0221
May 26, 2025
CurlyFalcon55
5 hours ago
J
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J
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k Reaper....
Happycat2   22
N Apr 29, 2025 by jlacosta
Can someone explain what the reaper is this time? I'm sorry but I don't know what "Rapper ear error a pear perrier ear ape ea games" means.
22 replies
Happycat2
Apr 27, 2025
jlacosta
Apr 29, 2025
J
Reaper....
G H J
Reveal topic tags
Reaper
L
G H BBookmark kLocked kLocked NReply
The post below has been deleted. Click to close.
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Happycat2
1456 posts
Happycat2
#1 h  Apr 27, 2025, 8:22 PM
Y by
Can someone explain what the reaper is this time? I'm sorry but I don't know what "Rapper ear error a pear perrier ear ape ea games" means.
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
bpan2021
2673 posts
bpan2021
#2 h  Apr 27, 2025, 8:34 PM
Y by
It says that intentionally; it's a mysterious message, I believe.
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
aidan0626
1966 posts
aidan0626
#3 h  Apr 27, 2025, 8:40 PM
Y by
from what i've heard, the cool down is about 1000^2 seconds long tho
This post has been edited 1 time. Last edited by aidan0626, Apr 27, 2025, 8:40 PM
Z Y
The post below has been deleted. Click to close.
This post has been deleted. Click here to see post.
Happycat2
1456 posts
Happycat2
#4 h  Apr 27, 2025, 8:40 PM
Y by
BRO ITS 11 DAYS LONG
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Happycat2
1456 posts
Happycat2
#6 h  Apr 27, 2025, 8:42 PM
Y by
Bro did u do that on putpose? The second I heard that i reap for 46 SECONDS and I had to wait 11 days :sob:
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justJen
1957 posts
justJen
#7 h  Apr 27, 2025, 8:42 PM
Y by
??? THE FINAL BOSS ???
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aidan0626
1966 posts
aidan0626
#8 h  Apr 27, 2025, 8:43 PM • 1 Y
Y by tyrantfire4
quote my post
i didn't lie about the cooldown
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Happycat2
1456 posts
Happycat2
#9 h  Apr 27, 2025, 8:43 PM
Y by
Can anyone else tell me if their cooldown is 11 days?
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aidan0626
1966 posts
aidan0626
#10 h  Apr 27, 2025, 8:44 PM
Y by
Happycat2 wrote:
Can anyone else tell me if their cooldown is 11 days?

the cooldown for everyone is the same
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Happycat2
1456 posts
Happycat2
#11 h  Apr 27, 2025, 8:45 PM
Y by
oh bc like yk since its a new game and no one knows that rules, maybe they randomized the cooldown time.
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justJen
1957 posts
justJen
#12 h  Apr 27, 2025, 8:45 PM
Y by
the cooldown is 11 days. what you're seeing isn't a bug, they just want to mess with us.
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evt917
2428 posts
evt917
#13 h  Apr 27, 2025, 8:58 PM
Y by
bruh

this is messed up
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buddyram
693 posts
buddyram
#14 h  Apr 28, 2025, 4:25 AM
Y by
11 days is insane.. I just got nine minutes but i kinda regret not waiting just like two minutes longer
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MathPerson12321
3797 posts
MathPerson12321
#15 h  Apr 28, 2025, 4:47 AM
Y by
the end of reaper is here...
ppl that knew the cd and still reaped is being kinda dumb
This post has been edited 1 time. Last edited by MathPerson12321, Apr 28, 2025, 4:47 AM
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Yihangzh
1344 posts
Yihangzh
#16 h  Apr 28, 2025, 4:56 AM
Y by
The message decodes to this?:Drake has a new game
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MathPerson12321
3797 posts
MathPerson12321
#17 h  Apr 28, 2025, 5:15 AM
Y by
Yihangzh wrote:
The message decodes to this?:Drake has a new game

no it does not
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Yihangzh
1344 posts
Yihangzh
#18 h  Apr 28, 2025, 5:27 AM
Y by
MathPerson12321 wrote:
Yihangzh wrote:
The message decodes to this?:Drake has a new game

no it does not

rats
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Craftybutterfly
596 posts
Craftybutterfly
#19 h  Apr 28, 2025, 6:11 AM
Y by
Reaper is where you try to get the highest amount of seconds in between reeps (or as what other people say)
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AlleKoala11
6 posts
AlleKoala11
#20 h  Apr 28, 2025, 6:25 AM
Y by
what are we talking about
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Dragon_Yang
322 posts
Dragon_Yang
#21 h  Apr 28, 2025, 11:59 AM
Y by
Happycat2 wrote:
Can someone explain what the reaper is this time? I'm sorry but I don't know what "Rapper ear error a pear perrier ear ape ea games" means.

Rapper ear error a pear perrier ear ape ea games

maybe "Reaper here. Error appear. Play our epic games"

like when you say it out loud, the message added another r sound after every syllable, and messed up all the vowel sounds
This post has been edited 1 time. Last edited by Dragon_Yang, Apr 28, 2025, 12:03 PM
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peppermint_cat
227 posts
peppermint_cat
#22 h  Apr 28, 2025, 12:24 PM
Y by
justJen wrote:
??? THE FINAL BOSS ???

I REALLY hope this doesn't mean that they're ending reaper games.
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MathPerson12321
3797 posts
MathPerson12321
#23 h  Apr 28, 2025, 2:08 PM
Y by
Dragon_Yang wrote:
Happycat2 wrote:
Can someone explain what the reaper is this time? I'm sorry but I don't know what "Rapper ear error a pear perrier ear ape ea games" means.

Rapper ear error a pear perrier ear ape ea games

maybe "Reaper here. Error appear. Play our epic games"

like when you say it out loud, the message added another r sound after every syllable, and messed up all the vowel sounds

I got "reaper error" then "pair" then "reaper games" using a pronounciation technique
so i think concurrent games may happen
This post has been edited 1 time. Last edited by MathPerson12321, Apr 28, 2025, 2:09 PM
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jlacosta
655 posts
jlacosta
#26 h  Apr 29, 2025, 6:51 PM • 4 Y
Y by peppermint_cat, aidan0626, aayr, sbarrack
The Reaper game description is not meant to be a puzzle that has a specific meaning, but the staff member who set up this Reaper game is intentionally keeping the cooldown and win time a mystery for this round.

We hope that helps!
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