Thanks as always to Jane Street! Here is that blog post about 63-bit numbers. https://blog.janestreet.com/what-is-gained-and-lost-with-63-bit-integers/ My book is out in North America on the 21 January 2020. Pre-order now! http://bit.ly/humblepi Here are the numbers: 9,223,372,036,854,775,798 stops 2^63 = 9,223,372,036,854,775,808 7FFFFFFFFFFFFFF6 111111111111111111111111111111111111111111111111111111111110110 Here are the tweets: Neil Codling @neilcodling 👀 Help, our train home is making 9 quintillion stops. EIZrPtbW4AA3UL2.jpeg https://twitter.com/neilcodling/status/1190757074164170758 Daniel @drawRect Replying to @neilcodling Thanks for the tweet. What version of the app are you using? I thought we fixed this bug AGES ago. https://twitter.com/drawRect/status/1191033767760158720 Lia Buddle @LiaBuddle Replying to @neilcodling Had the same thing in 2017... EIc4CNJXsAATexO.jpeg https://twitter.com/LiaBuddle/status/1190982241914101760 Matt Parker @standupmaths Thanks everyone who sent me this amazing tweet! So, as always it’s probably a binary overflow problem and sure enough 2^63 = 9,223,372,036,854,775,808 which is close! https://twitter.com/standupmaths/status/1190940255974760448 We have a free Think Maths magic trick activity that teachers can use to introduce their students to binary. http://think-maths.co.uk/standupmaths-videos?yt-trains#train-stops CORRECTIONS - None yet, let me know if you spot any mistakes! Thanks again, as always, for Jane Street being my principal sponsor. https://www.janestreet.com/ Thanks to my Patreon supporters who help make these videos possible. Here is a random subset: Icaro Fonseca Timothy Lombard Andy B Nokui Peter Tracy Parry Brandon Lindsay Miller Support my channel and I can make more maths videos: https://www.patreon.com/standupmaths Filming and editing by Alex Genn-Bash Music by Howard Carter Design by Simon Wright MATT PARKER: Stand-up Mathematician Website: http://standupmaths.com/ Maths book: http://wwwh.umble-pi.com/ Nerdy maths toys: http://mathsgear.co.uk/