One fine day at a nursing home
Two grannies were sitting on a bench outside when an old man walks by.
One of the grandmas yelled out, "We bet we can tell exactly how old you are!"
"There is no way you could guess that, you old biddies," the man replied.
The other grandma said: "Sure we can! Just drop your pants 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 both yelled, "You're 87 years old!!!"
Standing with his pants down around his ankles, the old gentleman asked, "How in the world did you guess?"
Slapping their knees and grinning from ear to ear, the two old ladies giddily yelled in unison: "We were at your birthday party yesterday!"