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--The method of calculating on your fingers the possible number of hours you can sleep after being up later than you wanted.--

Sleep Math is usually only done when you know you have to get up early, wished you could just sleep in, and are stressing because you're afraid you might not get enough sleep.

With a normal, not exhausted brain, you could probably do this math in your head. However, since you are tired you have to go back to how you did math as a child, counting on fingers.
(Couple intended to go to bed 'early' this particular night, and instead, stayed up way late talking & watching old episodes of The Sopranos.)

After finally brushing teeth and getting ready for bed, girl notices guy using his fingers to count something, like this 30+ man is all of sudden a 5 year old--

Girl to Guy--"You must be doing Sleep Math"
by M circled and M3 April 29, 2011
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