2016 is a leap year because it is a multiple of 4 (and not a multiple of 100). The Gregorian Calendar system of leap years gives an average tropical year of 365.2425 days compared to the current true value of 365.2421891, but I think we can do better.

Yes, at the 1:20-ish point it should be «365.2421891 days» as is on the screen, not the «365.2521891 years» I say. Sorry, its been a busy week and I recored and edited the video a bit too quickly to spot Past Matts mistakes.

Read Adam Gouchers article here:
cp4space.wordpress.com/2012/09/12/lunisolar-calendars/

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MATT PARKER: Stand-up Mathematician
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