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k a March Highlights and 2025 AoPS Online Class Information
jlacosta   0
Mar 2, 2025
March is the month for State MATHCOUNTS competitions! Kudos to everyone who participated in their local chapter competitions and best of luck to all going to State! Join us on March 11th for a Math Jam devoted to our favorite Chapter competition problems! Are you interested in training for MATHCOUNTS? Be sure to check out our AMC 8/MATHCOUNTS Basics and Advanced courses.

Are you ready to level up with Olympiad training? Registration is open with early bird pricing available for our WOOT programs: MathWOOT (Levels 1 and 2), CodeWOOT, PhysicsWOOT, and ChemWOOT. What is WOOT? WOOT stands for Worldwide Online Olympiad Training and is a 7-month high school math Olympiad preparation and testing program that brings together many of the best students from around the world to learn Olympiad problem solving skills. Classes begin in September!

Do you have plans this summer? There are so many options to fit your schedule and goals whether attending a summer camp or taking online classes, it can be a great break from the routine of the school year. Check out our summer courses at AoPS Online, or if you want a math or language arts class that doesn’t have homework, but is an enriching summer experience, our AoPS Virtual Campus summer camps may be just the ticket! We are expanding our locations for our AoPS Academies across the country with 15 locations so far and new campuses opening in Saratoga CA, Johns Creek GA, and the Upper West Side NY. Check out this page for summer camp information.

Be sure to mark your calendars for the following events:
[list][*]March 5th (Wednesday), 4:30pm PT/7:30pm ET, HCSSiM Math Jam 2025. Amber Verser, Assistant Director of the Hampshire College Summer Studies in Mathematics, will host an information session about HCSSiM, a summer program for high school students.
[*]March 6th (Thursday), 4:00pm PT/7:00pm ET, Free Webinar on Math Competitions from elementary through high school. Join us for an enlightening session that demystifies the world of math competitions and helps you make informed decisions about your contest journey.
[*]March 11th (Tuesday), 4:30pm PT/7:30pm ET, 2025 MATHCOUNTS Chapter Discussion MATH JAM. AoPS instructors will discuss some of their favorite problems from the MATHCOUNTS Chapter Competition. All are welcome!
[*]March 13th (Thursday), 4:00pm PT/7:00pm ET, Free Webinar about Summer Camps at the Virtual Campus. Transform your summer into an unforgettable learning adventure! From elementary through high school, we offer dynamic summer camps featuring topics in mathematics, language arts, and competition preparation - all designed to fit your schedule and ignite your passion for learning.[/list]
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0 replies
jlacosta
Mar 2, 2025
0 replies
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postaffteff
JetFire008   4
N 2 minutes ago by JetFire008
Source: Internet
Let $P$ be the Fermat point of a $\triangle ABC$. Prove that the Euler line of the triangles $PAB$, $PBC$, $PCA$ are concurrent and the point of concurrence is $G$, the centroid of $\triangle ABC$.
4 replies
JetFire008
19 minutes ago
JetFire008
2 minutes ago
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i need help
MR.1   3
N 3 minutes ago by MR.1
Source: help
can you guys tell me problems about fe in $R+$(i know $R$ well). i want to study so if you guys have some easy or normal problems please send me
3 replies
MR.1
3 hours ago
MR.1
3 minutes ago
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D1010 : How it is possible ?
Dattier   6
N 7 minutes ago by whwlqkd
Source: les dattes à Dattier
Is it true that$$\forall n \in \mathbb N^*, (24^n \times B \mod A) \mod 2 = 0 $$?

A=172840090421781518678763921675392141786000436658021921275090402437796947824966464426797102
59525308036470431210259590181720483369539690621515342820528633073982816814653666658107757108
67856720572225880311472925624694183944650261079955759251769111321319421445397848518597584590
900951222557860592579005088853698315463815905425095325508106272375728975

B=227564340154808184720778276049144229526648735475052708528935496537676518846805227119017278
70644188547893224843051453107076145465733981826429238937805270372241433808862604677609912285
67577953725945090125797351518670892779468968705801340068681556238850340398780828104506916965
606659768601942798676554332768254089685307970609932846902
6 replies
Dattier
Mar 10, 2025
whwlqkd
7 minutes ago
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Checkers on the board
Didier2   0
11 minutes ago
Source: Khamovniki 2023 - 2024 (group 10 - 1)
On all black cells of $8 \times 8$ chess board, except for the $4 \times 4$ central square, there is a checker. In one move, a checker can jump over adjacent checker (diagonally), and this adjacent checker (that was jumped over) is removed. Is it possible to come up with a sequence of moves, so that only one checker is left on the board?
0 replies
Didier2
11 minutes ago
0 replies
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No more topics!
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ways to fill x 3x8 grid by 9 numbers having 6 already in fixed places
parmenides51   0
Nov 12, 2021
Source: Mathematics Regional Olympiad of Mexico Center Zone 2016 P1
The grid shown below is completed by choosing nine of the following numbers without repeating: $4, 5, 6, 7, 8, 12, 13, 16, 18, 19$. If the sum of the five rows are equal to each other and the sum of the three columns are equal to each other, in how many different ways is it possible to fill the grid?

$ \begin {array} {| c | c | c |} \hline 10 & & \\ \hline & & 9 \\ \hline & 3 & \\ \hline 11 & & 17 \\ \hline & 20 & \\ \hline \end {array} $

Note: The sum of the rows and the sum of the columns are not necessarily equal.
0 replies
parmenides51
Nov 12, 2021
0 replies
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ways to fill x 3x8 grid by 9 numbers having 6 already in fixed places
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Source: Mathematics Regional Olympiad of Mexico Center Zone 2016 P1
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parmenides51
30627 posts
parmenides51
#1 h  Nov 12, 2021, 7:33 PM
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The grid shown below is completed by choosing nine of the following numbers without repeating: $4, 5, 6, 7, 8, 12, 13, 16, 18, 19$. If the sum of the five rows are equal to each other and the sum of the three columns are equal to each other, in how many different ways is it possible to fill the grid?

$ \begin {array} {| c | c | c |} \hline 10 & & \\ \hline & & 9 \\ \hline & 3 & \\ \hline 11 & & 17 \\ \hline & 20 & \\ \hline \end {array} $

Note: The sum of the rows and the sum of the columns are not necessarily equal.
This post has been edited 1 time. Last edited by parmenides51, Nov 12, 2021, 7:33 PM
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