Math Trick for Leap Year

Credit: About.com

I've been dealing with insomnia the past few days. It leaves me a lot of time to think. Not about anything important mind you, just a menagerie of miscellaneous minutia I know.

One is how to know if any year was or will be a Leap Year.

I picked this up somewhere along my teaching career!

If the last two digits of the year are 00 or end in a number that is evenly divisible by 4, that year is a leap year. 

1700=leap year because the last two digits are 00.
2016=leap year because 16 is evenly divisible by 4.
1965=not a leap year because 65 is not evenly divisible by 4.

Yup, this is what I did the other night while I was not sleeping. 

Then I got on to the year 2525 which lead me to begin thinking about...

See, you really do want me to sleep! ;-)