This is "extra footage" from the main video on divisibility at: https://youtu.be/yi-s-TTpLxY
Featuring Professor Tony Padilla.
Card trick and shuffling videos on Numberphile: http://bit.ly/Cards_Shuffling
More Tony videos: http://bit.ly/Padilla_Numberphile
Want to wind up Tony? Get yourself an I Love Norrie sticker: https://teespring.com//i-love-norrie-numberphile
NUMBERPHILE
Website: http://www.numberphile.com/
Numberphile on Facebook: http://www.facebook.com/numberphile
Numberphile tweets: https://twitter.com/numberphile
Numberphile is supported by the Mathematical Sciences Research Institute (MSRI): http://bit.ly/MSRINumberphile
Videos by Brady Haran
Support us on Patreon: http://www.patreon.com/numberphile
Brady's videos subreddit: http://www.reddit.com/r/BradyHaran/
A run-down of Brady's channels: http://www.bradyharan.com
Sign up for (occasional) emails: http://eepurl.com/YdjL9