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

Thanks to Ohad from Israel for suggesting this problem! A square with side length 5 has its corner at the center of a square with side length 4. The two squares overlap, and the overlapping region has one side equal to 3 as shown in the diagram. What is the area where the two squares

Matt Parker has a new favourite number – again! More links & stuff in full description below ↓↓↓ Some notes from Matt on how far he has investigated: https://www.numberphile.com/cannon-ball-numbers Matt’s book “Humble Pi” via Maths Gear (signed and ships almost everywhere): http://bit.ly/Humble_Pi More Numberphile videos with Matt: http://bit.ly/Matt_Videos James Grime sphere packing: https://youtu.be/CROeIGfr3gs Lucas Numbers:

Have you ever heard of Mills’ Constant? Video supported by (& free book): http://www.audible.com/numberphile More links & stuff in full description below ↓↓↓ Several people have pointed out the n=4 prime is 2521008887 (we missed an 8) More on prime numbers: http://bit.ly/primevids This video features Dr James Grime – https://twitter.com/jamesgrime The Mills Proof is at:

This one stumped me! This problem is part of the AIME, a qualifying test for the US Mathematical Olympiad team. The talented students who take the AIME only average about 20 percent–it’s a hard test! Plus no calculators are allowed. Can you figure out this problem from the 1987 test? Learn the trick which results

The Great Courses Plus (free trial): http://ow.ly/C3FE30hIvhc This video features Dr James Grime. More links & stuff in full description below ↓↓↓ More James Grime on Numberphile: http://bit.ly/grimevideos James Grime: http://singingbanana.com Tackling the Minimal Superpermutation Problem: https://arxiv.org/abs/1408.5108 (Apparently I mucked up the copy/paste for the 1-6 superpermutation and, amazingly, people actually check this stuff… The

It’s not so simple to solve for this simple answer. Thanks to all patrons! Special thanks this month to: Richard Ohnemus, Michael Anvari, Shrihari Puranik, Kyle. WolframAlpha http://blog.wolframalpha.com/2013/04/26/get-real-with-wolframalpha-computing-roots/ https://www.wolframalpha.com/input/?i=cuberoot(8%2B3*sqrt(21))%2Bcuberoot(8-3*sqrt(21)) https://www.wolframalpha.com/input/?i=(8%2B3*sqrt(21))%5E(1%2F3)%2B(8-3*sqrt(21))%5E(1%2F3) 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 channel to feature math topics suggested by people around the world.

This is a tricky SAT/GRE type problem that most people miss. Can you figure it out? Desmos animation https://www.desmos.com/calculator/kiswg6p0q7 Sources https://www.thisisinsider.com/hard-sat-math-questions-test-practice-2018-3 https://www.prepscholar.com/gre/blog/gre-geometry-review-practice/ 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 channel to feature math topics suggested by people around the world. Support on Patreon to inspire mathematical discovery and

A breakthrough by a Numberphile viewer (with help from some computers). More links & stuff in full description below ↓↓↓ Extra footage: https://youtu.be/d6nUVa8EtlU Original video: https://youtu.be/wymmCdLdPvM See the paper by Sander Huisman: http://bit.ly/Sander_Paper Discussed by Tim Browning from the University of Bristol. Support us on Patreon: http://www.patreon.com/numberphile NUMBERPHILE Website: http://www.numberphile.com/ Numberphile on Facebook: http://www.facebook.com/numberphile Numberphile

This is a fun basketball problem with an unexpected result! Sources http://www.math.utah.edu/~palais/mst/frequency.pdf http://faculty.sfasu.edu/judsontw/putnam/putnam-week06-solution.pdf https://sites.math.northwestern.edu/~mlerma/problem_solving/putnam/easy_putnam_problems.pdf https://www.theringer.com/nba/2018/12/5/18126305/deandre-jordan-free-throws-mavericks https://www.basketball-reference.com/players/j/jordade01.html 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 channel to feature math topics suggested by people around the world. Support on Patreon to inspire mathematical discovery and make the world a better place:

Matt Parker discusses Tupper’s Self-Referential Formula. More links & stuff in full description below ↓↓↓ Matt’s book on Amazon (US): http://bit.ly/Matt_4D_US Matt’s book on Amazon (UK): http://bit.ly/Matt_4D_UK A little bit of extra footage from this video: http://youtu.be/wx22jdwn5zQ Thanks to our Patreon supporters… Herschal Sanders (from Susan) Today I Found Out Christian Cooper Ken Baron Greg

In the game of Tetris, there are 7 pieces, each made up of 4 square units. (The shapes are called “tetrominoes” in mathematical literature.) Here’s the puzzle. Can you use one of each piece to form a 7×4 rectangle? If so, find a way. If not, prove why it’s impossible. Thanks to Doctor Perkins for

More links & stuff in full description below ↓↓↓ Brady’s Movember Page: http://bit.ly/BradyMo See full description for list of Connect 4 links. John Tromp’s page: http://bit.ly/TrompNumberphile James Allen’s Connect Four book: http://bit.ly/AllenBook James Allen: http://james.fabpedigree.com/ OEIS: https://oeis.org/A212693 Victor Allis paper: http://bit.ly/AllisPaper 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

42 is the only remaining (eligible) number below 100 which has not been represented as the sum of three cubes… 33 was cracked by Andrew Booker from the University of Bristol. More links & stuff in full description below ↓↓↓ The original 33 video: https://youtu.be/wymmCdLdPvM The 74 cracked video: https://youtu.be/_-M_3oV75Lw Casting out nines: https://youtu.be/FlndIiQa20o Andrew

Just a short problem for the upcoming Pi Day! 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 channel to feature math topics suggested by people around the world. Support on Patreon to inspire mathematical discovery and make the world a better place: https://www.patreon.com/mindyourdecisions If

The internet is loving this math trick which makes many calculations much easier! Sources/references Fascinating little life hack, for doing percentages: x% of y = y% of x So, for example, if you needed to work out 4% of 75 in your head, just flip it and and do 75% of 4, which is easier.

The psychologist Max Wertheimer was friends with Albert Einstein. In 1934, he wrote a letter to Einstein that contained a simple brain teaser. Can you figure it out?Thanks to all patrons! Special thanks to: Shrihari Puranik, Richard Ohnemus, Michael Anvari, Kyle. We are the only channel to feature math topics suggested by people around the

Check out Brilliant (and get 20% off) by clicking https://brilliant.org/numberphile Featuring Ben Sparks — More links & stuff in full description below ↓↓↓ Golden seeds limited edition T-Shirt: https://teespring.com/NP-Seeds More Golden Ratio stuff: http://bit.ly/Golden_Ratio More Ben Sparks Numberphile videos: http://bit.ly/Sparks_Playlist Ben’s Twitter: https://twitter.com/SparksMaths Ben’s website: www.bensparks.co.uk Geogebra file Ben used: https://www.geogebra.org/m/YThycjQK#material/T8eKzDu5 Note on this video:

Matt Parker shows off his Magic Square party trick (unlike magicians, mathematicians often reveal their secrets). More links & stuff in full description below ↓↓↓ More Magic Square videos: http://bit.ly/MagicSquareVideos Rubik’s Cube videos: http://bit.ly/rubiksvids More Matt on Numberphile: http://bit.ly/Matt_Videos A little extra bit for this video: https://youtu.be/zhB2AUNcsx0 Parker Square: https://youtu.be/aOT_bG-vWyg Parker Square T-Shirt: http://bit.ly/ParkerSquareTshirt Support

More links & stuff in full description below ↓↓↓ Abandoning “The Fifth Axiom” – Euclid’s so-called Parallel Postulate – gave birth to a whole new world… the world Hyperbolic Geometry. Featuring Dr Caleb Ashley. Extra footage from this interview: http://youtu.be/0FG-vUSjoAM Filmed at MSRI. More hyperbolic geometry videos soon. http://bit.ly/HyperbolicGeometry Euclid’s Postulates: http://mathworld.wolfram.com/EuclidsPostulates.html Support us on

Dr James Grime is back and talking about tortoises. More links & stuff in full description below ↓↓↓ In many ways this video follows on from http://www.youtube.com/watch?v=bFNjA9LOPsg and then http://www.youtube.com/watch?v=CMP9a2J4Bqw James Grime’s website is: http://singingbanana.com 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

Thanks to Himanshu from India for sending me this problem! It was part of a math competition where you had about 1 minute to solve each problem (I admit I took much longer). Can you figure out the area of the folded rectangle? 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 Thanks to

Oxford ranks as one of the best universities in the world. Can you solve this problem, which is adapted from an admission interview question? Source http://www.ox.ac.uk/admissions/undergraduate/applying-to-oxford/guide/interviews Desmos animation https://www.desmos.com/calculator/86hptwtqwb Websites consulted in research http://mathematicsbhilai.blogspot.com/2015/12/locus-of-mid-point-of-falling-ladder.html http://www.mathematische-basteleien.de/ladder.htm https://www.geogebra.org/m/ZUAcBme2 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 channel to feature math topics

Free audio book from Audible: http://www.audible.com/numberphile The book on Amazon: http://amzn.to/1fKe4Yo More links & stuff in full description below ↓↓↓ Author Simon Singh discusses mathematics in the TV show Futurama – specifically taxicab numbers and the great Ramanujan. This video features 1729 and 87539319 among its stars. More from Simon Singh at: About Brady’s mo…