The Problems with Secret Santa
Dr Hannah Fry discusses Secret Santa, anonymity and derangements. And a better way to do it.
More Hannah on Numberphile: http://bit.ly/hannah_vids
Hannah's co-written Xmas book: http://amzn.to/2g8mIn6
Hannah's love/math book: http://bit.ly/frylovebook
Numberphile poster: https://store.dftba.com/products/numberphile-poster
Graham's Number T-Shirt: https://store.dftba.com/collections/numberphile/products/grahams-number-shirt
Other Numberphile T-Shirts: https://teespring.com/stores/numberphile
Hannah on Objectivity: https://youtu.be/ayzKlPIcRKU