A blonde holding a baby walks into a drug store
and asks the clerk if she can use the store's baby
scale.

"Sorry, ma'am," says the clerk. "Our baby scale
is broken. But we can figure the baby's weight if
we weigh mother and baby together on the adult
scale, and then weigh the mother alone, and
subtract the second number from the first."

"Oh, that won't work," says the blonde.

"Why not?" asks the clerk.

"Because," she answers, "I'm not the mother -
I'm the aunt."