28th June is a Perfect Day to enjoy some Mathematics!
Perfect because 28 and 6 are both perfect numbers. You can easily check for properties of any number with Tanya Khovanova’s Number Gossip where we learn that 28 does not only have the rare property of being perfect, it is also composite, even, happy, odious, practical, triangular and Ulam! You can browse all the properties here.
28 is also happy! Happy Numbers – a favourite investigation, Dr Who knows about happy primes!
It’s also National Tau Day! Pi is wrong…..
This video provides a short version of the Tau Manifesto (14 minutes)