To wrap up the year 2019 Samuel Hansen is joined by Katie Steckles and Christian Lawson-Perfect of Aperiodical.com to discuss some of the big stories from the world of mathematics this year. The stories they discuss include Hannah Fry's Royal Institution Christmas Lectures, Karen Uhlenbeck's Abel Prize, year two of the Big Internet Math Off, a new multiplication algorithm, a new pi digits record, 33 and 42 as the sum of three cubes, and advances toward solutions for Collatz and Riemann. Music: lowercase n