Three old mischievous Grandmas were sitting on a bench  outside a nursing  home.   About then an old Grandpa walked by, and one of the old  Grandma's yelled  out saying, "We bet we can tell exactly how old you are." 
 
The old man said, "There ain't no way you can guess it,  you old fools."  One of the old Grandmas said, "Sure we can! Just drop your  pants and  under shorts and we can tell your exact age."
 
Embarrassed just a little, but anxious to prove they couldn't do it, he  dropped his drawers.
 
The Grandmas asked him to first turn around a couple of  times and to jump  up and down several times. Then they all piped up and  said, "You're 87  years old!"
 
Standing with his pants down around his ankles, the old gent asked,  "How in the world did you guess?" Slapping their knees and grinning from ear to ear, all three old ladies  happily yelled in unison-- "We were at your birthday party  yesterday!"

lol.....crazy bats