A farmer comes home to find his sheepdog waiting for him.
The sheepdog says: “I herded the sheep into the barn, just like you asked!
“You sure you got them all?” the farmer replies.
“Yep! All 40 of them!” says the sheepdog.
“40? But I only have 37 sheep.” Replies the farmer.
The sheepdog answers: “I know. I rounded them up for you.”