Math

The 17th annual Brazilian Olympiad featured an incredibly tricky logic puzzle that went viral on social media. Thanks to Guilherme who suggested and translated the problem from Portuguese to English! Pinocchio problem discussions https://ultimosegundo-ig-com-br.translate.goog/brasil/2022-06-08/questao-obmep-pinoquio-viraliza-personagem-mentiu.html?_x_tr_sl=auto&_x_tr_tl=en&_x_tr_hl=en-US&_x_tr_pto=wapp Students make memes involving Pinocchio and leak reactions A question about Pinocchio. What is your opinion about alternative C? from askphilosophy
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Three squares are formed on the three sides of an equilateral triangle. Each square has a side length equal to 1. What is the radius of the circle that circumscribes the squares? Thanks to Royce for the suggestion! This comes from the 2021 Colin Doyle Mathematics Competition in Australia. Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Send me suggestions by
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Thanks to Juanci for the suggestion! Also thanks to everyone who shared a solution on Twitter. A special thanks to LuisAndrRomero2 who provided the first detailed solution. Special thanks this month to: Michael Anvari, Kyle. Thanks to all supporters on Patreon! http://www.patreon.com/mindyourdecisions Who can solve this one? I'm working on a video for it and
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If you’ve been watching, you should be able to solve this one! Solutions on the web https://artofproblemsolving.com/wiki/index.php/1984_AIME_Problems/Problem_3 https://web2.0calc.com/questions/another-one-of-my-triangle-questions http://jwilson.coe.uga.edu/MATH7200/ProblemSet4.3.htmlSubscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Send me suggestions by email (address in video). I consider all ideas though can’t always reply! Like many YouTubers I use popular software to prepare my videos. You can search for animation software tutorials on
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Thanks to Moaaz for the suggestion! Can you solve this challenging geometry problem? 0:00 Problem 0:55 Solution 1 3:09 Solution 2 Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Send me suggestions by email (address at end of many videos). I may not reply but I do consider all ideas! If you purchase through these links, I may be compensated for
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Thanks to Francisco from Portugal for the suggestion! They say Euler asked this tricky algebra problem to his students. Reference Euler’s Riddle Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Send me suggestions by email (address in video). I consider all ideas though can’t always reply! Like many YouTubers I use popular software to prepare my videos. You can search for
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Check out Brilliant (and get 20% off their premium service): https://brilliant.org/numberphile (sponsor) More links & stuff in full description below ↓↓↓ This video features Dr James Grime – http://singingbanana.com Catch James in a recent Objectivity video with Brady: https://youtu.be/B4gzt8v401Q More James Grime videos on Numberphile: http://bit.ly/grimevideos More videos on Perfect Numbers: http://bit.ly/PerfectNumbers Triperfect T-Shirt… US:
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What is the distance between towns A and B? Learn how to solve this mysterious problem–a similar problem was a question to quality for the US Math Olympiad! Sources Qbyte Nick’s mathematical puzzle, number 75 http://www.qbyte.org/puzzles/p075s.html AoPS 2017 AMC 10A, problem 9 (US Olympiad qualifying test) https://artofproblemsolving.com/wiki/index.php/2017_AMC_10A_Problems/Problem_9 Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Send me suggestions by email (address
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What is the fewest number of moves which can solve any Rubik’s Cube? It’s God’s Number. More links & stuff in full description below ↓↓↓ See our full series of Rubik’s Cube videos at: http://www.youtube.com/playlist?list=PLt5AfwLFPxWJNAdHv8TUCOmj7iKqyHZeg This video features Matt Parker, James Grime and Katie Steckles. More about Matt’s record attempt and those solving helpers at
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I’m sorry the clip from the show has been blocked. For more on game theory in Breaking Bad, see my post: Game Theory in Breaking Bad If you like my videos, you can support me at Patreon: http://www.patreon.com/mindyourdecisions Connect on social media. I update each site when I have a new video or blog post,
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Previous video sets this up: https://youtu.be/-ruC5A9EzzE Extra on concatenation: https://youtu.be/LgnoYsbI7Uc More links & stuff in full description below ↓↓↓ We appreciate any help on Patreon – it lets us make a few more and better videos: http://www.patreon.com/numberphile Matt Parker on Numberphile playlist: http://bit.ly/Matt_Videos Matt’s channel: http://bit.ly/StandUpMaths Parker Square T-Shirt: http://bit.ly/ParkerSquareTshirt Inder J. Taneja papers… Single
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This inequality is famous in math competitions and in theoretical proofs. But why is it true? The video presents a great geometric visualization and proof for two variables. Pay attention–I’ll use this inequality in an upcoming video! Desmos.com link https://www.desmos.com/calculator/6kbruja3wb Link to proofs of generalized case https://artofproblemsolving.com/wiki/index.php?title=Root-Mean_Square-Arithmetic_Mean-Geometric_Mean-Harmonic_mean_Inequality Playlist to watch all videos on MindYourDecisions This
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A short preview of some stuff we’re filming for the new numberphile channel. Please subscribe. More links & stuff in full description below ↓↓↓ You can also follow us on Twitter and Facebook. NUMBERPHILE Website: http://www.numberphile.com/ Numberphile on Facebook: http://www.facebook.com/numberphile Numberphile tweets: https://twitter.com/numberphile Subscribe: http://bit.ly/Numberphile_Sub Videos by Brady Haran Patreon: http://www.patreon.com/numberphile Brady’s videos subreddit: http://www.reddit.com/r/BradyHaran/
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This is one of the harder calculus problems I’ve come across. Thanks to Nguyen Huynh Khoi from Vietnam for the suggestion! Solution from https://khoahoc.vietjack.com/question/84520/cho-ham-so-f-x-co-dao-ham-va-lien-tuc-tren-doan-4-8 Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Send me suggestions by email (address at end of many videos). I may not reply but I do consider all ideas! If you purchase through these links, I may
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This equation has a secret meaning. #shorts Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Send me suggestions by email (address at end of many videos). I may not reply but I do consider all ideas! If you buy from the links below I may receive a commission for sales. (As an Amazon Associate I earn from qualifying purchases.) This has
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Ultimate Tic Tac Toe, also known as Nine Board Tic Tac Toe, is an interesting variation on the classic game. The board is composed of a 3×3 grid of Big Squares. Inside of each Big Square is another 3×3 grid, so there are 9 Small Squares inside each Big Square. The position you play in
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There’s an incredible method to calculate the square root of a perfect square in your head. MIT Entrace Exam Arithmetic 1876 WayBackMachine: https://web.archive.org/web/20190404065722/https://libraries.mit.edu/archives/exhibits/exam-entrance1876/arithmetic1876.html Square root method Burning Math http://burningmath.blogspot.com/2013/09/extracting-square-roots-mentally-at.html Square root method proof Math StackExchange https://math.stackexchange.com/questions/2069192/why-does-this-method-for-finding-the-square-root-of-a-number-work Square root method Grey Matters http://gmmentalgym.blogspot.com/2010/10/root-extractions.html#rtsqr Hindu-Arabic numeral system https://en.wikipedia.org/wiki/Hindu%E2%80%93Arabic_numeral_system Laplace quote https://en.wikipedia.org/wiki/History_of_the_Hindu%E2%80%93Arabic_numeral_system#Impact_on_arithmetic Laplace picture https://en.wikipedia.org/wiki/File:Laplace,_Pierre-Simon,_marquis_de.jpg Abacus picture https://en.wikipedia.org/wiki/Abacus#/media/File:Houghton_Typ_520.03.736_-_Margarita_philosophica.jpg
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Thanks to Matej for suggesting this problem! This is from a math competition for 14 year olds in Croatia. While the problem is challenging, “you should be able to solve it” using elementary geometry and algebra. Can you figure it out? Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Playlist to watch all videos on MindYourDecisions: https://www.youtube.com/playlist?list=UUHnj59g7jezwTy5GeL8EA_g This is the only
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In 1880, James Garfield contributed a new proof of geometry’s most famous right triangle theorem. Mathematical treasure: Garfield’s proof https://www.maa.org/press/periodicals/convergence/mathematical-treasure-james-a-garfields-proof-of-the-pythagorean-theorem Engraved portrait https://en.wikipedia.org/wiki/File:GARFIELD,_James_A-President_(BEP_engraved_portrait).jpg Gizmodo post https://gizmodo.com/james-garfield-was-the-only-u-s-president-to-prove-a-m-1037750658 Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Send me suggestions by email (address at end of many videos). I may not reply but I do consider all ideas! If you purchase through these links,
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This is a standard question to prepare for India’s famously challenging JEE Advanced exam. Here is one way to solve the question quickly. Thanks to Avinash for the suggestion! Special thanks this month to: Daniel Lewis, Robert Zarnke, Kyle, Mike Robertson. Thanks to all supporters on Patreon! http://www.patreon.com/mindyourdecisions Problem credit to David Altizio (section 3
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Why five-sided figures pose a problem from Professor John Hunton – and a bit about the importance of Penrose Tiling. More links & stuff in full description below ↓↓↓ Professor Hunton works at the University of Leicester. NUMBERPHILE Website: http://www.numberphile.com/ Numberphile on Facebook: http://www.facebook.com/numberphile Numberphile tweets: https://twitter.com/numberphile Subscribe: http://bit.ly/Numberphile_Sub Videos by Brady Haran Patreon: http://www.patreon.com/numberphile
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A tetrahedron and a pyramid have edges of equal length. If they are glued together on a triangular face with the vertices aligned, how many faces will the new shape have? This question is trickier than it looks! It stumped the test-makers. Playable demonstration: Steve Phelps has made a Geogebra worksheet that you can try
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The Big Bang Theory TV is now part of math history: there’s a theorem named after Sheldon. Sources Siouxland News article https://siouxlandnews.com/news/local/morningside-college-professors-math-appearing-in-the-big-bang-theory 73 is the best number – Big Bang Theory clip Proof of the Sheldon conjecture https://math.dartmouth.edu/~carlp/sheldon02132019.pdf 73 is the best number (other properties) Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Playlist to watch all videos on MindYourDecisions: https://www.youtube.com/playlist?list=UUHnj59g7jezwTy5GeL8EA_g
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Can you solve this problem that stumped many advanced math students? References https://io9.gizmodo.com/ready-this-simple-puzzle-once-stumped-96-of-americas-1698814691 https://www.theguardian.com/science/2017/jun/05/did-you-solve-it-are-you-in-the-smartest-10-per-cent https://www.mapleprimes.com/posts/206713-Puzzle-Or-A-Simple-Exercise http://puzzles.nigelcoldwell.co.uk/seventytwo.htm https://timss.bc.edu/timss1995i/TIMSSPDF/C_full.pdf Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Send me suggestions by email (address in video). I consider all ideas though can’t always reply! Like many YouTubers I use popular software to prepare my videos. You can search for animation software tutorials on YouTube
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Colin Rizzio became famous after finding a mistake on the S.A.T. Sources https://www.deseret.com/1997/2/7/19293720/math-question-on-the-sat-didn-t-sit-well https://people.com/archive/flunking-the-tester-vol-47-no-7/ https://www.chicagotribune.com/news/ct-xpm-1997-02-07-9702070268-story.html https://www.dartmouth.edu/~chance/chance_news/recent_news/chance_news_6.03.html Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Send me suggestions by email (address in video). I consider all ideas though can’t always reply! Like many YouTubers I use popular software to prepare my videos. You can search for animation software tutorials on YouTube to
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Thanks to Dhrubajyoti for the suggestion! A similar problem was asked to class 10 students in India (Q33 from SMO junior 2016). I admit that this one stumped me. Can you figure it out? Solution presented: post by Thomas Hill on Quora https://www.quora.com/In-a-triangle-ABC-AB-AC-angle-BAC-100-circ-Let-D-be-a-point-such-that-B-is-an-interior-point-of-AD-and-AD-BC-How-can-you-find-angle-BDC Other solutions http://jwilson.coe.uga.edu/EMT668/EMT668.Folders.F97/Rapley/EMT725/100deg/100deg.html http://jwilson.coe.uga.edu/EMT668/EMAT6680.F99/Wise/essay1/essay1.htm https://gogeometry.blogspot.com/2011/11/problem-685-isosceles-triangle-100-40.html pic.twitter.com/NNSkNX2I5w — José Luis da Vila (@jldavilaa01)
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Large factorials and the use of Stirling’s Approximation. Featuring Professor Ken McLaughlin. More links & stuff in full description below ↓↓↓ Professor McLaughlin is based at Colorado State University: https://www.math.colostate.edu/~kenmcl/ We filmed this during his time at the Mathematical Sciences Research Institute. 69 Factorial: https://www.youtube.com/watch?v=kw6l_uTakRA Numberphile is supported by the Mathematical Sciences Research Institute (MSRI):
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Thanks to Ryan from India for the suggestion! Two candles of equal height but different thickness are lit. The first burns off in 8 hours and the second in 10 hours. When will the first candle be half the height of the second? Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Send me suggestions by email (address at end of many
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Can you solve this neat geometry puzzle? Thanks to Joe M. for the suggestion! Sources https://brilliant.org/practice/circle-properties-level-2-3-challenges/?problem=day-5-five-golden-circles&subtopic=circles&chapter=circle-properties How I’m Learning to Step into Math Problems Circle puzzle Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Send me suggestions by email (address in video). I consider all ideas though can’t always reply! Like many YouTubers I use popular software to prepare my videos.
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A compilation of Numberphile sound checks – Brady typically asks “what did you have for breakfast” so he can monitor audio levels. More links & stuff in full description below ↓↓↓ Previous sound checks with scientists here: http://youtu.be/4anqDfgQneA Support us on Patreon: http://www.patreon.com/numberphile NUMBERPHILE Website: http://www.numberphile.com/ Numberphile on Facebook: http://www.facebook.com/numberphile Numberphile tweets: https://twitter.com/numberphile Subscribe: http://bit.ly/Numberphile_Sub
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17 is the minimum number of clues required to give a unique sudoku solution – but how did mathematicians prove this? Featuring James Grime. More links & stuff in full description below ↓↓↓ Dr James Grime discusses a recent paper which cracked the problem. The paper being discussed by McGuire and others is at http://arxiv.org/abs/1201.0749
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A 6’28” version of our “Pi with Pies” calculation. More links & stuff in full description below ↓↓↓ Videos features Matt Parker who tweets at https://twitter.com/standupmaths The Pi-inspired music in the video explained: http://periodicvideos.blogspot.co.uk/2013/03/pimusic.html Our full collection of Pi videos at http://bit.ly/W4oDN1 While the pies are usually delicious, this batch was not for consumption (even
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Our Pi Playlist (more videos): http://bit.ly/PiPlaylist How accurately can we calculate Pi using hundreds of REAL pies? More links & stuff in full description below ↓↓↓ Extended version of this video (director’s slice) at http://www.youtube.com/watch?v=x4kyFKyCMv0 This video features Matt Parker: https://twitter.com/standupmaths Matt believes this is the world’s most accurate pie-based Pi calculation. More Pi videos:
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Thanks to Victor for the suggestion! A version of this problem appeared on a Kangaroo math competition for 12-13 year olds. Can you figure it out? Special thanks this month to: Michael Anvari, Daniel Lewis, Robert Zarnke, Kyle, Mike Robertson. Thanks to all supporters on Patreon! http://www.patreon.com/mindyourdecisions Original Math Kangaroo question on YouTube Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1
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Matt Parker explores the work of William Shanks – and boots up the ShanksBot. More links & stuff in full description below ↓↓↓ Matt Parker’s 2022 Pi Day Video: https://youtu.be/dtiLxLrzjOQ Discussing William Shanks on Objectivity: https://youtu.be/7yTXMeiVBCc Prime Number playlist: https://bit.ly/PrimePlaylist Pi playlist: http://bit.ly/PiPlaylist Matt Parker website: https://standupmaths.com Numberphile is supported by the Mathematical Sciences Research
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Cliff Stoll is passionate about Klein Bottles. More links & stuff in full description below ↓↓↓ Don’t miss the video about how he uses a robot to store 1,000 bottles UNDER his house… https://youtu.be/-k3mVnRlQLU More videos on Klein Bottles: http://bit.ly/KleinBottles ACME Klein Bottles: http://bit.ly/ACME_Klein Support us on Patreon: http://www.patreon.com/numberphile NUMBERPHILE Website: http://www.numberphile.com/ Numberphile on Facebook:
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People often email me that my videos helped them get a tech or finance job, which is really awesome, and I want to do more to help! So in this video I’m sharing a problem based on an interview question asked at Facebook. Source https://www.glassdoor.com/Interview/You-re-about-to-get-on-a-plane-to-Seattle-You-want-to-know-if-you-should-bring-an-umbrella-You-call-3-random-friends-of-y-QTN_519262.htm (Note: I re-uploaded this video with corrections. The original calculations
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Another pass at the Monty Hall Problem – see the last video and a new “express explanation” at: http://bit.ly/MontyHallProb More links & stuff in full description below ↓↓↓ Support us on Patreon: http://www.patreon.com/numberphile NUMBERPHILE Website: http://www.numberphile.com/ Numberphile on Facebook: http://www.facebook.com/numberphile Numberphile tweets: https://twitter.com/numberphile Subscribe: http://bit.ly/Numberphile_Sub Numberphile is supported by the Mathematical Sciences Research Institute (MSRI):
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