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 l 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 under shorts and we can tell your exact age."
Embarrassed just a little, he dropped his drawers.
The Grandmas asked him to turn around a couple of times, asked him to
jump up and down for a little while and then they all piped up and said,
"You're 84 years old!"
"How in the world did you guess?"
The old Grandmas snickered and laughed.
Slapping their knees and grinning from ear to ear, all three happily yelled in unison,
"Because we were at your birthday party yesterday."