Math

You open a brand new deck of cards, which has cards in increasing order by suit. You give the deck a random shuffle. How many cards, on average, do you expect to be in the exact same position as before you shuffled the deck? The video presents a solution that many find to be counter-intuitive.

A number which could earn its “finder” a $1000 prize. More links & stuff in full description below ↓↓↓ John Conway videos: http://bit.ly/ConwayNumberphile Read more at: http://gladhoboexpress.blogspot.co.uk/2017/06/whats-so-special-about-13532385396179.html With thanks to James Davis. Numberphile is supported by the Mathematical Sciences Research Institute (MSRI): http://bit.ly/MSRINumberphile We are also supported by Science Sandbox, a Simons Foundation initiative dedicated

This is one of the trickiest word problems I have seen. #shorts #math #mathematics #maths Via Quora reply of J. Lin https://www.quora.com/Whats-the-hardest-SAT-math-problem-that-youve-seen 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

More Ron Rivest videos: http://bit.ly/RonRivest Cryptography playlist: http://bit.ly/crypto_videos More links & stuff in full description below ↓↓↓ Ron Rivest: http://people.csail.mit.edu/rivest/ Computerphile: https://www.youtube.com/user/computerphile Numberphile is supported by the Mathematical Sciences Research Institute (MSRI): http://bit.ly/MSRINumberphile We are also supported by Science Sandbox, a Simons Foundation initiative dedicated to engaging everyone with the process of science. https://www.simonsfoundation.org/outreach/science-sandbox/ And

A magic square is a grid of numbers where every row, column, and diagonal has the same sum. Ancient Chinese mathematicians developed a clever method to make magic squares, the Lo Shu method, a technique that is even inspiring current research to make solar panels more efficient. #Shorts The Lo Shu Method From “The Evolution

This is a fun little problem; thanks to Pradeep Hebbar for the suggestion! Post on Quora https://qr.ae/TZFy7x Math StackExchange help https://math.stackexchange.com/questions/3486090/circle-inscribed-between-quarter-circles-proving-its-center-point 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

Katie Steckles on Pancake Numbers.. Signup for your FREE trial to The Great Courses Plus here: http://ow.ly/EJwH30fiZ1d More links & stuff in full description below ↓↓↓ More Numberphile videos with Katie: http://bit.ly/Steckles_Playlist Katie Steckles website: http://bit.ly/stecks_web Animation in this video by Pete McPartlan Numberphile is supported by the Mathematical Sciences Research Institute (MSRI): http://bit.ly/MSRINumberphile We

Leibniz is credited as one of the inventors of calculus, but this simple probability question tripped him up. If you roll two dice, is a sum of 11 or 12 more likely? #Shorts Leibniz error Damn, Leibniz…is this actually true? by inmath Leibniz picture https://en.wikipedia.org/wiki/Gottfried_Wilhelm_Leibniz#/media/File:Christoph_Bernhard_Francke_-_Bildnis_des_Philosophen_Leibniz_(ca._1695).jpg Stanford Encyclopedia of Philosophy https://plato.stanford.edu/entries/leibniz/ Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Send me suggestions

Tom Crawford on the mathematics of where river water goes when it hits the sea. See all three Navier-Stokes videos at: http://bit.ly/NavierPlaylist More links & stuff in full description below ↓↓↓ Tom Crawford works at the University of Oxford… more at: https://tomrocksmaths.com Playlist: http://bit.ly/NavierPlaylist Part 1 (Navier-Stokes): https://youtu.be/ERBVFcutl3M Part 2 (Reynolds Number): https://youtu.be/wtIhVwPruwY Rivers with

Who needs a calculator when you can do math in your head? Why The Method Works (Proof): https://www.youtube.com/watch?v=HF1vUuZDCTk 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, so you can follow me on whichever method

You really need to have seen the main video for this to make sense! More links & stuff in full description below ↓↓↓ MAIN VIDEO: http://youtu.be/lFQGSGsXbXE CONTINUATION: http://youtu.be/qbkH_0TNdk0 AND EVEN MORE: http://youtu.be/uENSO785aEI PLUS CUT FROM PART ONE: http://youtu.be/hggcjvdCihc Featuring Zvezdelina Stankova – Professor of Mathematics at Mills College, Director of Berkeley Math Circle, UC Berkeley

Featuring Simon Singh – catch him on the latest Numberphile Podcast too… https://youtu.be/kOttzKC33Vk More links & stuff in full description below ↓↓↓ Catch the Numberphile Podcast at: http://bit.ly/Numberphile_Pod_Playlist or at https://www.numberphile.com/podcast/ More videos with Simon on Numberphile: http://bit.ly/SimonSinghPlay Simon has written a book about math in The Simpsons and Futurama… And other books… https://amzn.to/2N05qJn Futurama

The 1947 Stanford Competitive Examination included a version of this problem. Reference https://www.cut-the-knot.org/Outline/Arithmetic/DivisionBy72.shtml 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 learn how to

Pi is the ratio of a circle’s circumference to its diameter. But how do we know the ratio is the same for every circle? The Elements of Plane Geometry By Charles Austin Hobbs · 1896 https://www.google.com/books/edition/The_Elements_of_Plane_Geometry/M8oUAQAAMAAJ?hl=en&gbpv=1&pg=PA215&printsec=frontcover 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

Professor Laurence Eaves on Pythagorean Primes – and why 5, 13 and 137 are three of his favourites!? More links & stuff in full description below ↓↓↓ More on prime numbers: http://bit.ly/primevids Fine structure constant on sixtysymbols at http://www.youtube.com/watch?v=WlSLIW0gZtk 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

Spearheading a Lune. Featuring Barry Mazur. More links & stuff in full description below ↓↓↓ Reddit discussion: http://redd.it/2hze46 Read more at http://bit.ly/Mazur_Essay and http://bit.ly/SquarableLunes Squaring the circle: http://youtu.be/CMP9a2J4Bqw Barry’s Blobs: http://youtu.be/ItiFO5y36kw (scalability) 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

If an octagon with equal sides is cut from a rectangle with sides of 4 and 6, what is the side length of the octagon? It’s a pretty fun problem to work out! Adapted from suggestion on Twitter @preshtalwalkar a regular octagon cut from a rectangle length and breadth 6 and 8 cm. What is

Scale and Similarity. More links & stuff in full description below ↓↓↓ Storyteller: Barry Mazur, Harvard University Moral of the Story – http://youtu.be/kiN_c403bkk Book by Barry: http://amzn.to/1rZpuJ2 Animation: Pete McPartlan — http://www.petemcpartlan.co.uk Music: Alan Stewart — http://bit.ly/1sdwTHF More Pete animated videos: http://bit.ly/PeteAnimate 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 problem is tricky even for people who are good with numbers. Can you make 24 from the numbers 3, 3, 8, 8? You can use the operations + – × ÷ ( ). You have to use all four numbers (the digit 3 two times and the digit 8 two times). There are no

If a ball’s velocity always equals exactly its position, how long will it take to reach x = 10, if it starts at x = 1?Thanks to Kaan and Fatih Ulupinar for suggesting this problem! 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

Tadashi is back, this time looking at drooping paper (and toilet paper). More links & stuff in full description below ↓↓↓ Subscribe to Numberphile and never miss a floppy paper video: http://bit.ly/Numberphile_Sub Playlist of Tadashi Tokieda videos: http://bit.ly/tadashi_vids Pizza and Gaussian curvature: https://youtu.be/gi-TBlh44gY Support us on Patreon: http://www.patreon.com/numberphile NUMBERPHILE Website: http://www.numberphile.com/ Numberphile on Facebook: http://www.facebook.com/numberphile

Can you see the pattern? Apparently geniuses can figure out the answer right away. Source https://puzzling.stackexchange.com/questions/19823/mensa-iq-test-question 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:

Get a free Audio Book: http://www.audible.com/numberphile Supereggs, Superellipses and Sergels torg – featuring Alex Bellos. More links & stuff in full description below ↓↓↓ Extra from this interview: http://youtu.be/Wxk-iiW7rxI Donald Knuth and his Piet Hein superellipse: http://youtu.be/v678Em6qyzk Alex Bellos: http://bit.ly/BellosBooks 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

In a list of 10 statements, the nth statement says there are exactly n false items in the list. Which of the statements, if any, are false? What if the nth statement says there are “at least” n false items? The video presents a solution to this mind-twisting logical problem. My blog post for this

Brady Numbers T-Shirt: http://bit.ly/T-Shirt-BN Part One of Golden Ratio Trilogy More links & stuff in full description below ↓↓↓ The new “Brady Sequence” demonstrates why Fibonacci Numbers are not so special. Featuring Matt Parker. Next in the trilogy: http://youtu.be/dTWKKvlZB08 Matt’s signed book (& extra goodies): http://bit.ly/Matt_Signed Amazon (UK): http://bit.ly/Matt_4D_UK Amazon (US): http://bit.ly/Matt_4D_US Discuss this video

A prime number “gift” from a mathematicians leaving his college. More links & stuff in full description below ↓↓↓ Featuring Tadashi Tokieda. More Tadashi: http://bit.ly/tadashi_vids Professor McKee explains: “Most of the digits of p were fixed so that: (i) the top two thirds made the desired pattern; (ii) the bottom third ensured that p-1 had

If every worker’s birthday has to be a holiday for all workers, how many workers should a company hire? There are some surprises in this fun little problem! Sources Frederick Mosteller’s “Fifty Challenging Problems in Probability with Solutions”. Fifty Challenging Problems in Probability with Solutions Dartmouth Chance News https://www.dartmouth.edu/~chance/chance_news/recent_news/chance_news_10.05.html#solution Math StackExchange https://math.stackexchange.com/questions/3355880/related-to-a-puzzle-which-is-larger-365-cdot-365-cdot-frac36436536 Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Send

The explanation was surprisingly really, really good. ChatGPT https://chat.openai.com/ homework question https://www.gauthmath.com/solution/1-The-graph-of-y-x-1-7-is-reflected-across-the-y-axis-What-is-an-equation-of-the-1714404645170181 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 purchases made on Amazon. As an Amazon Associate I

Thanks to: http://www.audible.com/numberphile More links & stuff in full description below ↓↓↓ This video features Dr Sarah Wiseman from UCL on numbers that are familiar – and things that can go wrong in our brains. Editing and animation in this video by Pete McPartlan. Books available on Audible by Numberphile people include: Alex’s Adventures in

This is said to be one of the trickiest GRE test questions. #math #maths #mathematics #shorts VERY HARD – ETS GRE Practice test, sectoon 6, #21 byu/ICUstunner inGRE 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