Featuring Neil Sloane… Check out Brilliant (and get 20% off their premium service): https://brilliant.org/numberphile (sponsor) More links & stuff in full description below ↓↓↓ Trapped Knight T-Shirt: https://teespring.com/en-GB/numberphile-trapped-knight Neil Sloane is creator of the On-Line Encyclopedia of Integer Sequences: https://oeis.org For more on the sequences and diagrams in this video, you can start at: https://oeis.org/A316667

Featuring Professor Carlo Séquin – see more from him at: http://bit.ly/carlosequin More links & stuff in full description below ↓↓↓ More on this topic soon… Animation by Pete McPartlan: http://bit.ly/PeteMcPartlan 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

This is a pretty tricky problem. Can you solve for the angle? Watch the video for the solution. I thank Barry, and I thank Akshay Dhivare from India for suggesting the problem via email. Sources https://gogeometry.blogspot.com/2008/05/elearn-geometry-problem-10.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

Numberphile is also on Facebook: http://www.facebook.com/numberphile More links & stuff in full description below ↓↓↓ 142857 is the most “famous” of the intriguing cyclic numbers. Featuring Dr Tony Padilla from the University of Nottingham – https://twitter.com/DrTonyPadilla 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

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

Photomath can’t solve this, and neither can Mathway, Symbolab, or Desmos. Can you? I explain how you can. A similar problem was given to high school students in Massachusetts, and you really have to know what you’re doing to figure it out. Thanks to all patrons! Special thanks this month to: Shrihari Puranik Richard Ohnemus

This is a really fun geometry problem. It comes from the UKMT, a test which is part of forming the Olympiad team in the UK. Thanks to Liam for sending it to me! 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

George Dantzig, William Sidis, Srinivasa Ramanujan? Who was the real Good Will Hunting? More links & stuff in full description below ↓↓↓ Maths in Good Will Hunting: http://www.youtube.com/watch?v=iW_LkYiuTKE This video features Numberphile’s very own mathematics superstar – Dr James Grime. 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

Squarespace: http://www.squarespace.com/numberphile This video features Hannah Fry – https://twitter.com/fryrsquared More links & stuff in full description below ↓↓↓ More on this topic (and lizards): http://youtu.be/Z8lv2vy5vco And even more on this topic: http://youtu.be/ygHwBxWyI6E The paper: http://bit.ly/RPSpaper Reddit for this video: http://redd.it/2tq25k Art and animation by Pete McPartlan Support us on Patreon: http://www.patreon.com/numberphile NUMBERPHILE Website: http://www.numberphile.com/ Numberphile

Multiplying by lines is a fun way to visually multiply numbers. This is why how you can use it for advanced examples. I wrote about the details in a book: “Multiply Numbers By Drawing Lines” https://www.amazon.com/gp/product/1500866148/ Watch the intro video first: https://www.youtube.com/watch?v=0SZw8jpfAk0 00:25 Numbers different # digits (122×13) 01:12 The digit 9 (19×11) 02:25 Negative

The famed Poincaré Conjecture – the only Millennium Problem cracked thus far. More links & stuff in full description below ↓↓↓ Ricci Flow (used to solve the problem): http://youtu.be/hwOCqA9Xw6A Riemann Hypothesis: http://youtu.be/d6c6uIyieoo Extra interview footage with Jim Isenberg: http://youtu.be/7eJleW0JcKg Grigori Perelman’s paper: http://bit.ly/perelmanpaper Discussed here by Katie Steckles and James Isenberg. Support us on Patreon:

Thanks to Nikhil Patro for suggesting this problem! What is the sum of the corner angles in a regular 5-sided star? What if the star is not regular, what is the sum of corner angles then? There are some neat ways to solve this. I present my favorite methods. Thanks to all patrons! Special thanks

More videos with Dr Holly Krieger: http://bit.ly/HollyKrieger More links & stuff in full description below ↓↓↓ Dr Holly Krieger is based at Murray Edwards College, University of Cambridge. Want some chemistry videos? Brady does those too: https://www.youtube.com/periodicvideos More on centrifuge problem via Matt Baker: https://mattbaker.blog/2018/06/25/the-balanced-centrifuge-problem/ Numberphile is supported by the Mathematical Sciences Research Institute (MSRI):

This is good practice for math Olympiad type problems. I thank Mirza for suggesting the problem, and since I couldn’t figure it out, I also thank Mirza for sending the solution. Can you figure it out? Sources #simple_core_math_exercise#玩玩系列 Gepostet von QED Math Blog am Freitag, 24. August 2018 Quite interesting. I stared at it for a

The ancient Babylonians used a number system with base 60 (sexagesimal). More links & stuff in full description below ↓↓↓ Tablet image courtesy of Bill Casselman and Yale Babylonian Collection – more at http://www.math.ubc.ca/~cass/Euclid/ybc/ybc.html This video features Thomas Woolley – he tweets at https://twitter.com/#!/thomasewoolley NUMBERPHILE Website: http://www.numberphile.com/ Numberphile on Facebook: http://www.facebook.com/numberphile Numberphile tweets: https://twitter.com/numberphile Subscribe:

This problem is baffling many people on Facebook and Twitter. Can you figure it out? I thank everyone who emailed it to me, with a special thanks to the first two people: Riadh Temala from Tunisia; and Shivam Varma from India. 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

The Batman Curve was a viral hit. Here we show you some of its building blocks. More links & stuff in full description below ↓↓↓ Here’s the old reddit post: http://www.reddit.com/r/pics/comments/j2qjc/do_you_like_batman_do_you_like_math_my_math/ Featuring Dr James Grime. 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

Part One: https://youtu.be/wGkvyN6s9cY Featuring Tadashi Tokieda. More links & stuff in full description below ↓↓↓ More Tadashi videos: http://bit.ly/tadashi_vids Raw paperclips slow motions: https://youtu.be/zuX5yy_93JA Video by Brady Haran and Pete McPartlan (animations by Pete) 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

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

Prime numbers, Ulam Spirals and other cool numbery stuff with Dr James Grime. More links & stuff in full description below ↓↓↓ James Clewett on spirals at: http://youtu.be/3K-12i0jclM And more to come soon… * subscribing to numberphile does not really change your physical appearance! And “golden line” in this context was made up by Brady!

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

First in a series of videos about knots. Here we have Carlo H. Séquin from UC Berkeley. More links & stuff in full description below ↓↓↓ More videos to come at: http://bit.ly/Knot-a-Phile Edit and animation by Pete McPartlan. Film and interview by Brady Haran With thanks to Rob Scharein for the use of his software

Everyone’s details below in full description. Please leave a comment about YOUR favourite number!!! More links & stuff in full description below ↓↓↓ Thanks YouTube EDU people. This video featured in order: Brady Haran (who makes Numberphile): http://www.bradyharan.com/ Derek Muller chose i – http://www.youtube.com/1veritasium Hank Green chose 2 – http://www.youtube.com/scishow Steve Spangler chose 13 –

This challenging geometry problem appeared on one of the hardest math competitions (the Putnam exam), and there is a neat way to solve it! Thanks to all patrons! Special thanks this month to: Shrihari Puranik Kyle Professor X Richard Ohnemus Erik J. (for spotting multiple errors in my posts!) Sources https://mks.mff.cuni.cz/kalva/putnam/psoln/psol787.html https://iastate.app.box.com/s/r8zqykcivi84tftyy8j51uxo8j5l7no0 Subscribe: https://www.youtube.com/user/MindYourDecisions?sub_confirmation=1 Playlist