The biggest number we've ever tackled - TREE of Graham's Number. Supporting #TeamTrees on a quest to plant 20 million trees - https://www.teamtrees.org/ (Original brown papers from this video available to support the campaign - http://bit.ly/brownpapers) More links & stuff in full description below ↓↓↓ Extra footage from this interview: https://www.youtube.com/watch?v=wqdOnEnfJXM Big Numbers: http://bit.ly/Big_Numbers More on Graham's Number: https://www.youtube.com/watch?v=XTeJ64KD5cg Ron Graham videos: http://bit.ly/Ron_Graham More on TREE(3): https://www.youtube.com/watch?v=3P6DWAwwViU Moon Trees: https://www.youtube.com/watch?v=6qGbkFhxYhs Video guides to Tree Species: http://bit.ly/TreesPlants 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 support from Math For America - https://www.mathforamerica.org/ 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 Numberphile T-Shirts: null Brady's videos subreddit: http://www.reddit.com/r/BradyHaran/ Brady's latest videos across all channels: http://www.bradyharanblog.com/ Sign up for (occasional) emails: http://eepurl.com/YdjL9